Chase mortgage payment datapoint
I just received a confirmation email from Chase mortgage that my 2 Plastiq payments have been processed. So the timeline is:
8/14: Submitted payments on Plastiq using AGC.
8/19: Received "check mailed" notification email from Plastiq
8/23: Received payment processed email from Chase.
So 9 days total, including 4 weekend days. Not bad at all!