Earlier today, ~adnano submitted a patch to a repo I own:
https://lists.sr.ht/~ancarda/vcs-autodiscovery/patches/29093

This was to add a link to the README file, which I applied and
pushed.

This looks fine on sr.ht (hub), but not git.sr.ht. Opening
https://git.sr.ht/~ancarda/vcs-autodiscovery-rfc/ I noticed
"RFC.md" actually links here:
https://git.sr.ht/~adnano/test/tree/master/RFC.md

I think the patch was pushed to ~adnano/test first (currently
404), before being applied by me. Perhaps there's some caching
issue as the link is relative: `[RFC.md](RFC.md)', so it's not
clear when it would have to be regenerated.

Can I file a ticket? And for now, could someone refresh the
README?

Yes, you can file a ticket for this. Thanks!