was about to say the same thing. off just the upstairs unit water. if the water stops. then its confirmed its upper units water piping (which 90% chance it is).

but upper unit also need to confirm that the lower unit is not the cause of it. such as drill/hacking ceiling which may cause pipes to rattle/crack.

The issue normally arises when both parties didnt do anything and pipe leaks. so of course everyone say. its management to fix as they didnt take care of pipe.

good luck.