Disappearing/blinking stroke while reshaping or changing the stroke size of the object in stage

Everytime I draw with stroke tools - pencil tool, pen tool, shape tools (line tool , rectangle tool, eclipse tool, polystar tool), all primitive tools, pencil tools, and paintbrush tool.  The stroke is randomly disappear while reshaping the object or changing the stroke size.

Stroke disappearing whing reshaping the object.

Stroke disappearing while changing the stroke size. In the video you can see the stroke start disappearing when its sizes is 3, and 15

I used Adobe Animate 2020 ver 20.5.1 on Windows 10 with NVIDIA Geforce GTX 1050ti graphic card , 16 GB ram and Intel core i5-7500 CPU