Sorting by weight causes a 500 error
Can be reproduced by going to Merge Requests and sorting either by "Less weight" or "More weight"
Somewhere between RC1 and RC3 this problem was introduced. See the spike in issues since RC3 was deployed to GitLab: https://sentry.gitlap.com/gitlab/gitlabcom/issues/7040/
MRs can't be assigned weight, so that's presumably why this happens. A test should also be written to prevent this in the future.