Same issue
Same issue here. I hit the spend threshold last week and paid it immediately and I need the MQMs to count for 19 to keep my status in 20.
I looked at my delta account and my miles from AmEx seem to hit on the 10th of the following month. So I hit threshold in early December, pay in early December but likely that miles likely not credited until 1/10/20. Going to be really pissed if they don’t count toward 19 as I was prepaying bill, buying gift cards etc to hit the threshold by year end. Ugh!