I try to change a folder with initial capital letters to lowercase and then find that a non-existent path prompt appears.

• Make sure there is no history.
• fish --private -C "cd /tmp; mkdir Debug"
• Enter the command: mv Debug debug shows mv Debug Debug ( This issue is tracked in Suggestions are confusing when case differs #3134 )
• Delete the first D of the second parameter and try to change it to lowercase.
  • mv Debug |ebug
  • mv Debug debug -> mv Debug Debug/ebug (/ebug is gray, pressing tab does not complete this part.)

It seems that the /ebug part shouldn't be there.

fish from master branch
Reproduced under macOS and Linux.