Apparently, the problem with Bugzilla and MySQL version 8 has been known for over 2 years.
I am running Bugzilla version 5. When my website provider upgraded my server to MySQL version 8, Bugzilla started throwing errors like the ones reported 2 years ago.
I have not been able to find any version of Bugzilla that mentions this error in its Release Notes. What version should I upgrade to?
https://bugzilla.mozilla.org/show_bug.cgi?id=1497042 says:
However, a comment on Stack Overflow claims that 5.0.6 didn't fix the issue. That was the most recent release on the 5.0 branch, according to https://www.bugzilla.org/releases/. So you might have to try the 5.1 branch.
If you have further compatibility issues, I think the best place to report it would be the site for Bugzilla issues (the link I gave above).
You may even have to fix the code in Bugzilla yourself. This is not rocket science, I had to modify Bugzilla once for a project.