Broken layer performance.
There is a problem when creating a new layer (exluding upper one). After using a brush tool (or any similar) some cubic areas, which seem to be unpainted, emerege in the center of canvas. Also they change location and from. It doesn't disappear after saving the document as well (jpg and psd). The bug also visible in earlier photoshop versions. In fact, both CC 18 (19.1.6) and CC 19 ( 20.0.2) (lag this way).
What can i do thix or avoid this problem? !