diff --git a/CLAUDE.md b/CLAUDE.md
index c5a4b00..3f52f58 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -97,7 +97,13 @@ expect Nix to report the correct hash on a failed build (or use `nix-prefetch`/`
     clears bootstrap/opcode cache, rebuilds `.env`, rsyncs static storage into `dataDir`, symlinks the runtime
     `app.php`, and guards one-time actions (`migrate`, `db:seed`, admin account creation) behind marker files
     (`.initial-migration`, `.db-seeded`, `.admin-created`) in `dataDir`. `phpfpm-invoiceninja.service` and
-    `invoiceninja-queue-worker.service` both depend on it.
+    `invoiceninja-queue-worker.service` both depend on it. It also unconditionally runs
+    `invoiceninja-manage cache:forget languages` on every activation, working around an upstream bug: migration
+    `2025_08_31_224356_additional_languages_af_ca_id.php` runs during `migrate` (before `db:seed`'s
+    `LanguageSeeder` has populated the other 42 rows) and does `Cache::forever('languages', Language::all())`,
+    permanently caching just the 3 languages it sees at that moment — without this, the language dropdown in
+    the app stays stuck at 3 entries forever, since `StaticServiceProvider` checks that cache key before ever
+    querying the DB again.
   - `invoiceninja-scheduler.timer`/`.service` run `artisan schedule:run` every minute — this is what drives
     Invoice Ninja's own internal cron-scheduled jobs (recurring invoices, scheduled reports, etc.); without it the
     app's dashboard reports "cron jobs are not enabled". Laravel's scheduler is just a dispatcher, so this one
diff --git a/nixos-module/invoiceninja.nix b/nixos-module/invoiceninja.nix
index 5a0d6c7..83432cd 100644
--- a/nixos-module/invoiceninja.nix
+++ b/nixos-module/invoiceninja.nix
@@ -696,6 +696,14 @@ in
         # Necessary for languages, currencies, countries, etc.
         [[ ! -f ${cfg.dataDir}/.db-seeded ]] && invoiceninja-manage db:seed --force && touch ${cfg.dataDir}/.db-seeded
 
+        # Work around an upstream bug: migration 2025_08_31_224356_additional_languages_af_ca_id.php
+        # runs during `migrate` (before db:seed's LanguageSeeder has populated the other 42 rows) and
+        # does `Cache::forever('languages', Language::all())`, permanently caching just the 3 languages
+        # it sees at that moment. Without this, the language list stays stuck at those 3 forever,
+        # since StaticServiceProvider checks this cache key before ever querying the DB again.
+        # Unconditional (not marker-gated) so it also self-heals installs that hit this before the fix.
+        invoiceninja-manage cache:forget languages
+
         # Create Invoice Ninja admin account
         [[ (! -f ${cfg.dataDir}/.admin-created) && (${
           if cfg.adminAccount.enable then "true" else "false"
diff --git a/tests/nixos-test.nix b/tests/nixos-test.nix
index 1590f3f..bcb81e5 100644
--- a/tests/nixos-test.nix
+++ b/tests/nixos-test.nix
@@ -21,6 +21,8 @@ pkgs.testers.nixosTest {
   };
 
   testScript = ''
+    import json
+
     def check_invoiceninja(machine, proxy_unit):
         machine.wait_for_unit("mysql.service")
         machine.wait_for_unit("redis-invoiceninja.service")
@@ -65,6 +67,19 @@ pkgs.testers.nixosTest {
             )
             assert "${adminEmail}" in login_response, f"login did not succeed: {login_response}"
 
+        with subtest("full language list is available, not just the af/ca/id migration's 3"):
+            # Regression check: migration 2025_08_31_224356_additional_languages_af_ca_id.php runs
+            # during `migrate`, before db:seed's LanguageSeeder has populated the other 42 rows, and
+            # does Cache::forever('languages', Language::all()) - permanently caching just the 3
+            # languages it sees at that moment. invoiceninja-data-setup works around this with
+            # `invoiceninja-manage cache:forget languages`; this confirms the workaround is in place.
+            token = json.loads(login_response)["data"][0]["token"]["token"]
+            statics = machine.succeed(
+                f"curl -sf http://localhost/api/v1/statics -H 'X-API-TOKEN: {token}'"
+            )
+            language_count = len(json.loads(statics)["languages"])
+            assert language_count > 40, f"expected ~45 languages, got {language_count}"
+
 
     nginx.start()
     caddy.start()