Tempo/Clocking glitch to watch out for!

My system was set to 48k.
I was sent stems to do overdubs but they were 44.1k.
I had already imported them…they were playing at the wrong speed/key.

I switched my Clock to 44.1k. Sounded normal.
I did not change the Tempo (wasn’t using click)
I did the overdubs and exported files and sent them back.

THEY DIDN"T LINE UP.
Something weird happened with the clocking and they were running a few BPM too fast.
Not 100% sure what happened but watch out for it.

If I had been using a click with my Tempo, I would have seen it.