If you update the template directory* setting to a new one.
Once removed the old one from the setting.
If the user have RW on folder:
LO provide to ERASE (!!!) the content from this.
(This is not safe in any way)
If the user have only R on folder:
Files stand still (of course).
Then if you try to restore the folder, templates become invisible and not avaiable.
*a shared folder in the network
I have two template directories listed in Paths on my laptop, one on the laptop itself and one on the network. If there is no reason to remove one except redundancy then don’t; if it is redundancy then it doesn’t matter that one is erased.
If you feel it is a bug then follow this link and file one: How to Report Bugs in LibreOffice - The Document Foundation Wiki
It was a question July 2021 with a self-no-answer.
I put it there so:
1 maybe on day it will be fixed
2 others unfortunate can google a more complete finding directly.
I eventually apprecciate an help to report this problem in the right place.
Thank you