Whether or not Paypal is "acting weird" , the important part is he doesn't want to pay.
Put him on your Blocked Bidder List.
If his feedback left for others is reasonable, send him a Mutual Cancellation, letting him know that a prompt agreement will release him from the transaction.\
If he sounds off in any way, wait for the four days and if he has not paid, start an Unpaid Item Dispute. This will also end the transaction but is safer for you since he will not be able to leave feedback.
