When the Drag Multiple Parts as Single Part option is enabled in Studio, grouped selections / models / etc. don’t respect the rotation of the surface they’re being dragged over. As you can see in the repro clip below, whenever you drag the model it doesn’t apply the correct rotation to force the selection to match with the surface, it almost seems like it’s working backwards or overshooting its target sometimes:
(just to be clear, the thing I’m dragging in the clip is a model)
This has been an issue for a while at this point, it was reported a year and a half ago here. Obviously it’s not hugely important but it’d be really nice to have this functionality back.