Apparently, Customer Support knows nothing about this. After emailing them a couple of times trying to explaing the issue (the Find and Replace funtion doesn't work to edit Item condition in bulk), I get the following answer:
"You need to go the scheduled relistings section and open the listing and select the "Item Condition" from the drop down option which is given at the right side of listing and then click on Relist Now or the Schedule Relist button."
In other words, you have to edit them (change the item condition) one by one! Now, it worked to do through Find and Replace a couple of days ago, mind you. But not now. And the "answers" to my questions to Customer Support are no answers at all.
Mike or Tony, do you guys know anything about it?