libreoffice calc comment displays wrong

Libreoffice calc (spreadsheet) comments display *part-cropped* when rollover mouse over cell,
so full comment *not* visible when rollover
but displays correct in full whe click "show comment" for individual cell or menu VIEW>Comments [to show all comments in sheet.
=on Libreoffice 7.4.1.2 on Ubuntu 20.04..1 / Linux 5.4 desktop.

Weird thing is that no problem on another linux machine (Laptop) with *same* Libreoffice version.

I think it was fine on desktop as well as laptop, until maybe recently desktop problem started.

Any ideas???

I've compared settings on both machines, finding no obvious significant difference, (or changing differences especially if re OS appearance such as font resolution or even icons themes -without any luck).

I even installed earlier Libreoff version (alongside exisiting latest 7.4.1.2), but still same prob.

*Screenshots available, but how can i post them here?
***Any ideas how to fix?