When pushing background color button in LO v.126.96.36.199 beta 2, sometimes instead of filling the cell with the desired color, it applies "no fill". I had selected "Document colors" palette, but I am not sure this have any importance.
Here is a small video that illustrates the problem (300kb):
Steps to Reproduce:
1. Select a cell an try to fill it with a color.
Sometimes it fills the cell right, soemtimes it just apply "no fill"
Fill the right color every time.
User Profile Reset: No
Thanks for reporting the issue.
It's a dupe of bug 118138 and it will be fixed in LibreOffice 6.1 RC1
*** This bug has been marked as a duplicate of bug 118138 ***