Renaming wiki page title throws 500 and appends paths instead of replacing

Summary

Renaming the wiki page after the last 9.5 update causes a 500 error on save, and also appends paths to the page instead of change the path.

Steps to reproduce

1. Create wiki page with path. e.g. test/Docs
2. Edit wiki page
3. Rename title to blah/Docs
4. Page throws 500 error on Save, even though it actually saves the change. (Maybe it's trying to redirect to the previous page which has a different name now?)
5. blah is added to the path, not replaced.
6. Even trying to use /blah/Docs appends the path again, as per the screenshot.

What is the current bug behavior?

• After renaming and pressing "Save changes" it goes to the old URL and I get a 500 error. (@jonaskello noted these two in the MR Original post)
• Changing the path in the title will append a new path, not change it.

What is the expected correct behavior?

I would assume that renaming a page with an existing path would remove the old path and add the new path. You could argue that renaming the page test/Docs with the title blah/Docs would result in test/blah/Docs, but in that case renaming with /blah/Docs should result in blah/Docs

Relevant logs and/or screenshots