I hope Anonymous people will soon get cleaned....
I found another bug related to layers.
https://imgur.com/a/mzp3vEH
Having 2 drawing layers, select 1 layer, click Fusion and error message pop instead of doing the "fusion all layers" that the 32bits version was doing.
Error: 0x80004005
RWpaint 64 (2023.1) french version.