Is PayPal running a new scam? At least I haven't encountered this. I received a message saying the funds had arrived, but they were supposedly "estimated transfer" They ended up being in transit for 10 days, never reached my account, and were returned to the customer. The client is accordingly silent and does not respond... in general, be careful

It was probably run as an eCheck transaction with their bank. Those have to fully clear first before funds are released.