Overwrite Existing Items - Not an Option

My team is having an issue updating a board that we generally update on a bi-weekly basis. Things have been working very smoothly up until this past week. We are on the Enterprise plan and there are almost 20,000 items on the board which should be fine. When we go to update from an excel file, we can only “Create new items” and they “Overwrite existing items” is not available anymore. This seems strange as it will allow the board to duplicate multiple items and then we have to go and manually delete the duplicates versus simply overwriting them.

Is there a reason for this or do we have to split up the board?

Update… Splitting up the board does not make a difference. Even if we only have 20 items in a board now, we still do not have the option to “Overwrite Existing Items”. This started happening late last week.

Have you opened a support case with monday.com support as well? This sounds like a possible bug or feature regression.