Yes, it is a copy paste error when someone copy pastes it from some other column (along with the formatting) instead of manually typing it it unfortunately ruins the whole sheet. Since the sheet is protected by the admin we do not have access to correct such mistakes.
That is why it is advisable for a single person or 1-2 people to update the sheet for everyone in the month (like I do it for the May sheet so it is relatively more clean). This ensures that the formatting is correct and there is uniformity across the sheet. Since we can't restrict the access, we need to live with it.
Fun fact, people also copy paste the formulas at the end of the sheet and it screws up the processing time calculations for the entire month as well
