Workflow doesn't show up in UI workflow list or API

[SimonWoidig]

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Hello. I have a problem with listing workflows.
We are using a workflow dispatcher (https://github.com/benc-uk/workflow-dispatch) that calls the Github API to list all workflows in the repository. The response JSON doesn't have the expected workflow(s). First I thought the issue was in that action but I have looked over the source code and found nothing wrong.
Well after some exploring I tried calling the API manually. I don't see the workflow in the UI and neither in the API response (/repos/actis-sro/SOME-REPO/actions/workflows).
The actual workflow file is present in the .github/workflows directory, right next to other workflow files, of which some are present in the UI (and API) and some are not.
I am willing to provide more information via a more private channel.

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[SimonWoidig]

Just tried switching the default branch to a different one and back and suddenly all the workflows have shown up.