Guest users do not have access to unprotected cells

Hello dear community,

I hope someone can help me. I have many Excel tables on which guest contributors can also make entries.

I have a table on my Sharepoint that has a share link for everyone. Please refer

The cells in column B C E F are not protected. This means that the check mark under right click on the cells and format cells / protection tab is not set. Sheet protection is activated. Logged in users can now change these unprotected cells.
However, guest contributors with a release link cannot change these exact cells.
Things get really crazy when I enter something in column B as a logged in user. Then the guest user can also change what has just been entered. But this only works in column B.

I can't explain this strange behavior - oh yes, guest user entries worked until last week - but this problem only started this week.
And also very strange - the exact entries that a guest contributor made without any problems until last week can no longer even be changed by this guest contributor.

Many Thanks to all

Best regards

Alexander