Getting same issue. Transferred SPG to Marriott and transfer was near instantaneous. Booked hotel (and given confirmation) and then message about not enough points but yes you can book now and wait for points to arrive. Then given message about needing an e-cert. OK click on that and it wants to charge me $1500 for the stay lol.
Call in and they are clueless - CSR says they are reservations and have nothing to do with points but "it should be fine". Very reassuring. This is also a new hotel not open yet but will be in one week and we are staying there four weeks from now so perhaps that is why the e-cert message shows up as well. I will wait until tomorrow and see if it is any clearer.