I’ve have a number of spreadsheets I use daily and I have formatted certain columns for my date and number preference - every few days the formatting dissappears and goes back to the default - I then format the cells again, all is good for a few days and then it happens again.
Complement
I should have stated that shouldn’t I!
I’m Windows 10 64bit and its the installed versions of Calc & Writer I use (Version: 6.2.3.2 (x64))