Stable publish validation failed for org.freedesktop.Sdk.Extension.rust-stable

The build for `org.freedesktop.Sdk.Extension.rust-stable` failed validation during publication in the stable repository.

**Build Information:**
- Commit SHA: bdf80624848bfe0bf0c26ba26d434ac7715f8885
- Build ID: 313907
- Build log: https://github.com/flathub-infra/vorarbeiter/actions/runs/32734216459

**Validation Failure:**
```
1 out of 1 checks failed (flathub-hooks)

Check command cd "/tank/repo/builds/313907" && FLAT_MANAGER_BUILD_ID="313907" FLAT_MANAGER_JOB_ID="604468" "/usr/local/bin/flathub-hooks" "review" "-c" "/etc/flathub-hooks.json" exited unsuccessfully: exit status: 1, stderr: [2026-08-24T13:58:35Z INFO flathub_hooks::review] Refs present in build: ["runtime/org.freedesktop.Sdk.Extension.rust-stable/x86_64/25.08", "appstream2/x86_64", "appstream2/aarch64", "appstream/aarch64", "runtime/org.freedesktop.Sdk.Extension.rust-stable/aarch64/25.08", "appstream/x86_64", "runtime/org.freedesktop.Sdk.Extension.rust_stable.Sources/x86_64/25.08"]
[2026-08-24T13:58:35Z INFO flathub_hooks::review] Submitting appdata for review: ReviewRequest { build_id: 313907, job_id: 604468 }
[2026-08-24T13:58:36Z INFO flathub_hooks::utils] Failed to contact backend https://flathub.org/api/v2/moderation/submit_review_request: HTTP status server error (500 Internal Server Error) for url (https://flathub.org/api/v2/moderation/submit_review_request)
[2026-08-24T13:58:36Z INFO flathub_hooks::utils] Retrying (1/5) in 1 seconds...
[2026-08-24T13:58:38Z INFO flathub_hooks::utils] Failed to contact backend https://flathub.org/api/v2/moderation/submit_review_request: HTTP status server error (500 Internal Server Error) for url (https://flathub.org/api/v2/moderation/submit_review_request)
[2026-08-24T13:58:38Z INFO flathub_hooks::utils] Retrying (2/5) in 2 seconds...
[2026-08-24T13:58:41Z INFO flathub_hooks::utils] Failed to contact backend https://flathub.org/api/v2/moderation/submit_review_request: HTTP status server error (500 Internal Server Error) for url (https://flathub.org/api/v2/moderation/submit_review_request)
[2026-08-24T13:58:41Z INFO flathub_hooks::utils] Retrying (3/5) in 4 seconds...
[2026-08-24T13:58:46Z INFO flathub_hooks::utils] Failed to contact backend https://flathub.org/api/v2/moderation/submit_review_request: HTTP status server error (500 Internal Server Error) for url (https://flathub.org/api/v2/moderation/submit_review_request)
[2026-08-24T13:58:46Z INFO flathub_hooks::utils] Retrying (4/5) in 8 seconds...
[2026-08-24T13:58:55Z INFO flathub_hooks::utils] Failed to contact backend https://flathub.org/api/v2/moderation/submit_review_request: HTTP status server error (500 Internal Server Error) for url (https://flathub.org/api/v2/moderation/submit_review_request)
[2026-08-24T13:58:55Z INFO flathub_hooks::utils] Retrying (5/5) in 16 seconds...
[2026-08-24T13:59:12Z INFO flathub_hooks::utils] Failed to contact backend https://flathub.org/api/v2/moderation/submit_review_request: HTTP status server error (500 Internal Server Error) for url (https://flathub.org/api/v2/moderation/submit_review_request)
Error: Failed to contact backend https://flathub.org/api/v2/moderation/submit_review_request: HTTP status server error (500 Internal Server Error) for url (https://flathub.org/api/v2/moderation/submit_review_request)

Stack backtrace:
0: anyhow::error::::msg
1: ::post_review_request::{{closure}}
2: flathub_hooks::utils::retry
3: ::post_review_request
4: flathub_hooks::main
5: std::sys::backtrace::__rust_begin_short_backtrace
6: std::rt::lang_start::{{closure}}
7: std::rt::lang_start_internal
8: main
9: __libc_start_call_main
at ./csu/../sysdeps/nptl/libc_start_call_main.h:58:16
10: __libc_start_main_impl
at ./csu/../csu/libc-start.c:360:3
11: _start

```

cc @flathub/build-moderation

This issue is being opened for tracking by Flathub admins and may indicate an [infrastructure problem](https://status.flathub.org). Please do not close or modify this until an admin has responded.

Start with the linked GitHub Actions run and inspect the flathub-hooks review output, focusing on the repeated 500 responses from the moderation endpoint. Confirm whether the failure is an infrastructure problem and wait for the build-moderation admins to respond; done means the publication can be retried or the issue is otherwise acknowledged by an admin.

Written by the indexing model from the issue text.