Release Notes can't be saved - E500

Summary

We can't save any release notes - it resolves in an E500

Steps to reproduce

• Create and push tag
• Navigate to /-/tags
• Click on Edit for a tag
• Write stuff
• Click on save
• dead

Example Project

https://gitlab.com/k.boese/test-the-tag-bug/-/tags/t1 (i dont know about proper settings to allow anyone to do stuff, just copy the project... does this work on gitlab? i dont even think a test project is really neccessary, but nevermind)

(If you are using an older version of GitLab, this will also determine whether the bug is fixed in a more recent version)

What is the current bug behavior?

It does not save - fails doing so

What is the expected correct behavior?

It saves and re-shows the tag

Output of checks

This bug happens on GitLab.com