At present list of tags is showing all available tags. When a new branch is created on github, it is first built for amd64 and then for arm64. Test panel is running on arm64. That means a branch may be deployed before it is ready.
The response from docker hub includes what architectures are available, so it should be simple to filter down based on that:
https://hub.docker.com/v2/repositories/specifyconsortium/specify7-service/tags/?page_size=1