incorrect display using the remove tool

Hello community,

Since about two month I face the following problem using the latest lightroom classic verion13.3:

if I want to use the remove tool in the development section, the picture is transformed into somewhat monochrome with outlines! As soon as I quit the remove tool the normal pic appears again.

My System: 

iMac Mini M2 24GB macOS Sonoma 14.5

find attached screen shot movie

Can anyone advise me in this regared?

Help is very much appreciated.

Thank you.

Josef