Under test if you attempt to rename a table _xlcn then it will not accept it. The table can be renamed just xlcn (without the underscore).
The interesting thing is that the error message that I get indicates that the name must commence with a letter or underscore.
I do not know why the name is not accepted with the underscore. Possibly Excel uses _xcln somewhere that we cannot see and that is where the conflict occurs.
Suggest a work around of changing the name _xcln to something else.