Can't resave custom field definitions on multilingual sites
On multilingual site 5.10.3 (Joomla, but that shouldn't make a difference), I entered pre help for a custom field. Save. Edit again. Remove value from field. Save again. It hangs. Error in Civi log:
https://gist.github.com/JoeMurray/ec6eb90a42a78a5d9fd2b242739178af
Further testing showed it hangs on any edit. Dropping the index would let it save once, but hang on 2nd and subsequent attempts.