Hello,
The Linux version of Lunacy is very buggy.
It takes a while to open, and when it does, it freezes or there is a problem with the cursor
Hello!
I’ve asked about your OS and Lunacy versions in another thread, you may post them either here or in that thread. 
As for the cursor issue, is it this one? Mouse icon appears with a Fuzzy Box - Ubuntu 20 - #6 by samuelosoba