Still a bug in 2.4.2 Button disappearing in navbar


I asked this already, but there seemed no problem solving in the new update.
When adding a button in the navbar or using a class to turn a link in the nav bar int o a button,
the hover makes strange behaviour. It will never take the color you set in hover mode, it will just fade into 0 transparency.
When using a “hero” bloc and giving a class to a link everything works, it just doesn’t work with the navbar. Is there any solution I spent hours trying to make it work without success.

EDIT: works fine with solid outlines just not with fills