This is a really nasty feature. I had an item for sale that was automatically re-listing as expected each time the auction ended without any bidders. After a few rounds of that, and lowering the price, I put an end to the madness (or so I thought) by canceling the auction. After I ended it, I returned to the Active screen and it was empty. Good. I then gave the item away and forgot about it.
A month goes by... Suddenly this morning I get an email from eBay (the first since I ended the auction manually) that says my item sold, and the buyer paid for it! Wha?? I looked in my item history and saw that it actually re-listed itself AFTER I had manually canceled the auction and confirmed that my "Active" dashboard was clear. And on top of that, it no longer sent me any email communications that my auction was live, or being relisted, or getting bids. Not until it WON did I get any notification.
This meant I had to refund buyer ASAP as item is no longer in inventory - which ran into a separate problem because PayPal no longer had sufficient funds to reimburse him due to a couple of tiny auto-payments into that account right after his last night. And it takes days to get PayPal's balance back up by transferring money from other accounts.
Meanwhile, I contacted eBay support to find out what went wrong, and they are writing this off as user error. They said that somewhere when I was canceling the auction (which had NO bidders, and not even any watchers) there is a checkbox for auto-relisting the item. Well why the heck would I ever want to auto-relist an item I just manually STOPPED? This is really bad UI/UX design. Per eBay:
"Starting in May 2019, when you successfully complete a cancelled item or remorse return for a single-quantity listing we'll provide you with a more convenient way to relist the item, which will help you resell the item and manage your business more efficiently. Upon completing a return or cancellation, a checkbox will be preselected for you that defaults to an automatic relisting of your item."
