Comment 4 for bug 1968869

Got it:
https://github.com/mixxxdj/mixxx/blob/f2d670edeb483efb066bf7f00255d01df2f0017c/src/library/previewbuttondelegate.cpp#L184

It happens when the mouse leaves the table from a hovered cell.
In this case we do not receive a cellEntered event from another cell that disables the Button overlay.

I have found this post with a suggested workaround:
https://www.qtcentre.org/threads/26044-QAbstractItemView-entered-signal-where-is-QAbstractItemView-left-signal

Now I can also confirm it on somehow on Ubuntu.
If I leave the cell over the left table border, during resizing the cell is painted delayed. When I leave the cell crossing other cells it paints normally.