@rosachs
It is a supposedly a test. It is presented as an option to "SOME" buyers so they have an opportunity to combine shipping for auctions. You, as a seller, don't get to pick/choose which buyers, and you can't turn it off other than basically turning off your default settings here:
https://www.ebay.com/bmgt/buyerrequirements
Buyer Rules:
*Require buyers to provide a payment method before they place a bid.
*Require buyers to provide a payment method before they make an offer.
Click submit or save.
Then you can for sure file the unpaid item cancellation after four days as before.
Needless to say, these Buyer Rules (aka Auto-Pay) settings requiring individual payments at full shipping costs was not really popular with buyers. For instance, should a buyer win six of your penny auctions for $5.00 shipping for each, they are going to pay $30 in shipping alone for six smashed penny coins. People see the "put up a payment source in order to proceed to bid" and likely just back out of your listings and find a seller who does not require this.
Yes, you might get paid faster, but you are likely getting paid less for lack of participants. eBay does not tell you how many buyers went to bid and simply left your listings instead. When this first started a seller could file the unpaid item cancellation after 96 hours anyway, and didn't have to wait a week. You can try that, or if it doesn't work anymore, you can turn the "Buyer Rules" off. If you truly don't wish to combine items for a buyer, you can certainly ditch the "auction" format, make everything fixed price with immediate payment required, and if you get more than one sale to the same buyer, keep the extra shipping if that is your goal.
