diff --git a/bootstrap/helpers/domains.php b/bootstrap/helpers/domains.php
index 8be6d9a77a..e904c34fe1 100644
--- a/bootstrap/helpers/domains.php
+++ b/bootstrap/helpers/domains.php
@@ -3,6 +3,7 @@
 use App\Models\Application;
 use App\Models\Service;
 use App\Models\ServiceApplication;
+use App\Models\ServiceDatabase;
 use Illuminate\Support\Collection;
 
 /**
@@ -591,6 +592,37 @@ function findServiceApplicationForEnvName(Service $resource, string $envServiceN
     return $resource->applications()->where('name', $resolved)->first();
 }
 
+/**
+ * Check if a service copies a SERVICE_FQDN_ / SERVICE_URL_ declaration of the application named in it.
+ * The copy (same key, same value) must not generate a domain or overwrite the variable (#11924).
+ * Declarations with another port or path share the host on purpose (for example Appwrite).
+ *
+ * @param  array<string, mixed>|Collection<string, mixed>  $services  Parsed compose services
+ */
+function isCopiedServiceUrlDeclaration(
+    Service $resource,
+    array|Collection $services,
+    ServiceApplication|ServiceDatabase $current,
+    string $key,
+): bool {
+    $owner = findServiceApplicationForEnvName($resource, parseServiceEnvironmentVariable($key)['service_name']);
+    if (! $owner || $owner->name === $current->name) {
+        return false;
+    }
+
+    // Same declaration sources as serviceParser: environment and build arguments.
+    $declarationsOf = fn (string $serviceName) => convertToKeyValueCollection(
+        collect(data_get($services, [$serviceName, 'environment'], []))
+            ->merge(data_get($services, [$serviceName, 'build', 'args'], []))
+    );
+    $ownerDeclarations = $declarationsOf($owner->name);
+    $currentDeclarations = $declarationsOf($current->name);
+
+    return $ownerDeclarations->has($key)
+        && $currentDeclarations->has($key)
+        && (string) $ownerDeclarations->get($key) === (string) $currentDeclarations->get($key);
+}
+
 /**
  * Put/update a service domain entry under the original compose service name,
  * removing legacy twin keys that resolve unambiguously to the same name.
diff --git a/bootstrap/helpers/parsers.php b/bootstrap/helpers/parsers.php
index 01a5b04a66..eb2d8b472e 100644
--- a/bootstrap/helpers/parsers.php
+++ b/bootstrap/helpers/parsers.php
@@ -2547,6 +2547,10 @@ function serviceParser(Service $resource): Collection
                 $port = $parsed['port'];
                 $fqdnFor = $parsed['service_name'];
 
+                if (isCopiedServiceUrlDeclaration($resource, $services, $savedService, $key->value())) {
+                    continue;
+                }
+
                 // Only ServiceApplication has fqdn column, ServiceDatabase does not
                 $isServiceApplication = $savedService instanceof ServiceApplication;
 
diff --git a/bootstrap/helpers/services.php b/bootstrap/helpers/services.php
index ca6cd6014d..dddb673ca5 100644
--- a/bootstrap/helpers/services.php
+++ b/bootstrap/helpers/services.php
@@ -313,8 +313,16 @@ function updateCompose(ServiceApplication|ServiceDatabase $resource)
             // Those belong to other services and will be updated when THOSE services are updated
         }
 
-        // Remove duplicates
-        $templateVariableNames = array_unique($templateVariableNames);
+        // Remove duplicates and copies of another application's declaration
+        $templateVariableNames = array_filter(
+            array_unique($templateVariableNames),
+            fn ($variableName) => ! isCopiedServiceUrlDeclaration(
+                $resource->service,
+                collect(data_get($dockerCompose, 'services', [])),
+                $resource,
+                $variableName,
+            ),
+        );
 
         // Extract unique service names to process (preserving the original case from template)
         // This allows us to create both URL and FQDN pairs regardless of which one is in the template
diff --git a/tests/Feature/ServiceSharedMagicUrlOwnerTest.php b/tests/Feature/ServiceSharedMagicUrlOwnerTest.php
new file mode 100644
index 0000000000..8da05c9222
--- /dev/null
+++ b/tests/Feature/ServiceSharedMagicUrlOwnerTest.php
@@ -0,0 +1,156 @@
+<?php
+
+/**
+ * Regression for #11924: when two compose services declare the same
+ * SERVICE_URL_<NAME>_<PORT> (old Twenty template: twenty + worker), the
+ * variable must follow the domain of the <NAME> application, not the domain
+ * of whichever service the parser processes last.
+ */
+
+use App\Models\Environment;
+use App\Models\InstanceSettings;
+use App\Models\Project;
+use App\Models\Server;
+use App\Models\Service;
+use App\Models\ServiceApplication;
+use App\Models\StandaloneDocker;
+use App\Models\Team;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+
+uses(RefreshDatabase::class);
+
+beforeEach(function () {
+    InstanceSettings::forceCreate(['id' => 0]);
+    $team = Team::factory()->create();
+    $server = Server::factory()->create(['team_id' => $team->id]);
+    $destination = StandaloneDocker::where('server_id', $server->id)->first()
+        ?? StandaloneDocker::factory()->create(['server_id' => $server->id]);
+    $project = Project::factory()->create(['team_id' => $team->id]);
+    $environment = Environment::factory()->create(['project_id' => $project->id]);
+
+    $this->service = Service::factory()->create([
+        'environment_id' => $environment->id,
+        'server_id' => $server->id,
+        'destination_id' => $destination->id,
+        'destination_type' => $destination->getMorphClass(),
+        'compose_parsing_version' => '5',
+        'docker_compose_raw' => <<<'YAML'
+services:
+  twenty:
+    image: twentycrm/twenty:v1.15
+    environment:
+      - SERVICE_URL_TWENTY_3000
+  worker:
+    image: twentycrm/twenty:v1.15
+    environment:
+      - SERVICE_URL_TWENTY_3000
+YAML,
+    ]);
+});
+
+it('keeps SERVICE_URL_TWENTY on the twenty domain when worker declares the same variable', function () {
+    $this->service->parse();
+
+    $twenty = $this->service->applications()->where('name', 'twenty')->first();
+    $twenty->update(['fqdn' => 'https://crm.example.com']);
+
+    $this->service->fresh()->parse();
+
+    $env = fn (string $key) => $this->service->environment_variables()->where('key', $key)->value('value');
+
+    expect($env('SERVICE_URL_TWENTY'))->toBe('https://crm.example.com')
+        ->and($env('SERVICE_FQDN_TWENTY'))->toBe('crm.example.com')
+        ->and($env('SERVICE_URL_TWENTY_3000'))->toBe('https://crm.example.com:3000')
+        ->and($this->service->applications()->where('name', 'worker')->value('fqdn'))->toBeNull();
+});
+
+it('does not overwrite SERVICE_URL_TWENTY when the worker domain is saved', function () {
+    $this->service->parse();
+    $this->service->applications()->where('name', 'twenty')->first()->update(['fqdn' => 'https://crm.example.com']);
+    $this->service->fresh()->parse();
+
+    // Installs parsed before the fix keep a generated domain on worker.
+    $worker = $this->service->applications()->where('name', 'worker')->first();
+    $worker->update(['fqdn' => 'http://twenty-stale.10.0.1.1.sslip.io']);
+
+    updateCompose($worker->fresh());
+
+    expect($this->service->environment_variables()->where('key', 'SERVICE_URL_TWENTY')->value('value'))
+        ->toBe('https://crm.example.com');
+});
+
+it('keeps path routing when services declare the same variable with another path or port', function () {
+    $this->service->update(['docker_compose_raw' => <<<'YAML'
+services:
+  appwrite:
+    image: appwrite/appwrite:1.7
+    environment:
+      - SERVICE_URL_APPWRITE=/v1
+  appwrite-console:
+    image: appwrite/console:6
+    environment:
+      - SERVICE_URL_APPWRITE_3000=/
+  appwrite-realtime:
+    image: appwrite/appwrite:1.7
+    environment:
+      - SERVICE_URL_APPWRITE=/v1/realtime
+YAML]);
+
+    $this->service->parse();
+
+    $domains = $this->service->applications()->pluck('fqdn', 'name');
+    $host = str($domains['appwrite'])->before('/v1')->value();
+
+    expect($domains['appwrite'])->toEndWith('.sslip.io/v1')
+        ->and($domains['appwrite-console'])->toBe($host)
+        ->and($domains['appwrite-realtime'])->toBe("{$host}/v1/realtime");
+});
+
+it('does not treat a build argument as a copy of the named application declaration', function () {
+    $this->service->update(['docker_compose_raw' => <<<'YAML'
+services:
+  twenty:
+    image: twentycrm/twenty:v1.15
+    environment:
+      - SERVICE_URL_TWENTY_3000
+  web:
+    image: nginx:alpine
+    build:
+      context: .
+      args:
+        - SERVICE_URL_TWENTY_3000=/admin
+YAML]);
+
+    $this->service->parse();
+
+    expect($this->service->applications()->where('name', 'web')->value('fqdn'))->toEndWith('/admin');
+});
+
+it('does not treat a service as a copy of a duplicate row with the same name', function () {
+    $this->service->update(['docker_compose_raw' => <<<'YAML'
+services:
+  app:
+    image: nginx:alpine
+    environment:
+      - SERVICE_URL_APP_80
+YAML]);
+    ServiceApplication::create(['name' => 'app', 'service_id' => $this->service->id, 'image' => 'nginx:alpine']);
+    ServiceApplication::create(['name' => 'app', 'service_id' => $this->service->id, 'image' => 'nginx:alpine', 'is_migrated' => true, 'fqdn' => 'https://app.example.com']);
+
+    $this->service->parse();
+
+    expect($this->service->environment_variables()->where('key', 'SERVICE_URL_APP')->value('value'))
+        ->toBe('https://app.example.com');
+});
+
+it('fixes SERVICE_URL_TWENTY for installs where worker already has a generated domain', function () {
+    $this->service->parse();
+    $this->service->applications()->where('name', 'twenty')->update(['fqdn' => 'https://crm.example.com']);
+    $this->service->applications()->where('name', 'worker')->update(['fqdn' => 'http://twenty-stale.10.0.1.1.sslip.io']);
+    $this->service->environment_variables()->where('key', 'SERVICE_URL_TWENTY')->first()->update(['value' => 'http://twenty-stale.10.0.1.1.sslip.io']);
+
+    $this->service->fresh()->parse();
+
+    expect($this->service->environment_variables()->where('key', 'SERVICE_URL_TWENTY')->value('value'))->toBe('https://crm.example.com')
+        ->and($this->service->applications()->where('name', 'worker')->value('fqdn'))->toBe('http://twenty-stale.10.0.1.1.sslip.io');
+});