Graphic issues in LO calc

I randomly get an area of field of my data sheet displayed wrong (see picture). Activating, deactivating anti-aliasing didnt help. When I scroll out of the area and back or overlap it with another window it appears normal again.
Iam using LO fresh ( but it also happens to me with the stable (5.1) version.
Any hints?


I cannot upload a photo because I do not have “3 Points” ??
So I see a lot of cells totally black, , sometimes half of the cell black, numbers crossed etc.