I was on DL40 from SLC-MSP (752) which continues to LHR as a 764. Same game there.

Related to this - before DL512 DTW-MSP was canx Friday night, the gate agents kept saying there had been an aircraft change from the 319 to an Maddog. The system would NOT let them move people to the appropriate seats. My hunch is that since MEX-DTW was still airborne, they could not pull up leg 2, yet another DL IT issue. Makes me wonder if that is why they ended up cancelling the flight and not because they could not find FAs. Shena thoughts dancing in my head.

IIRC, all but one time this year for me, 512 from DTW-MSP has been a MD88. The first leg MEX-DTW is always a A319.