shadow distortion/flicker issue when mouse move/zoom

[stj29]

First of all, I would like to congratulate you on your project. I would like to say that I admire your project.

But there is a problem that I cannot understand and cannot solve. There is a problem with shadow coloring during mouse movement or zoom movement. What causes this and how do I solve it?
I would be grateful if you could help.

[syzdev]

@stj29 Is there any progress?