I guess, your KS did not finish moving or renaming something. KS hanged. You had to terminate it, didn’t you?
I know Katalon Studio is buggy in moving/renaming testcases, testobjects and folders. 
See the following previous posts as evidence:
- Katalon Studio erased a Test Case code when it was moved, and then renamed
- Script code vanished when a test case is renamed - #30 by mike.verinder
- Urgent Test Collections test suite names disappeared with this error An internal error occurred during: "Test Suite Collection Builder". java.lang.NullPointerException - #13 by kazurayam
- Katalon Studio failed to rename a Keyword class
I am not surpised to hear you got a new problem in Katalon Studio while you moved/renamed something. Katalon dev team seems to me not keen on fixing this sort of primitive bugs. They seem to be too busy adding great features like AI-….
My advice
You should not move/rename anything in Katalon Studio. 
Seriously. I am not joking.
Instead, you should create a new Test Case with new name, and copy&paste the source code from the old to the new. Then you can safely remove the old one. This procedure is safe.
If you desperately need to move/rename things, before doing it, you should apply the version control system git to take local backups of your project frequently in case KS breaks your project due to bugs. Provided you have applied git, you have a chance to salvage your project out of corruption.