Collection import not working properly

I’m using the csv import to update my CMS items. I have a big collection of over 1000 items.
Now this worked before, however when importing the csv it no longer asks to update the items. I can only add the items, which results an new items instead of updated ones.

So it no longer shows the screen that there are already items in the collection with the question to update matching items.

Anyone has this problem also? And did you manage to get it fixed?

I have the same issue. Have you found a solution?