Ah, as far as I know, every credit has always posted for me in a relatively timely fashion, generally within days or at 7 days, at the most. The only exception was if I recall the PayPay $30 or $50 (can't recall which) credit for 6 months; during one of the months, it didn't post. I called and the CSR credited it immediately, only to see the credit come in a few weeks later. I unwittingly double dipped but they never clawed it back.
Not that I'm a big fan of PayPay or anything, but I'd love it if there were to do this again, say, at $100 credit this time!
PS - Oh, not that I really keep track but it does appear that I do receive less frequent email confirms.