Not strictly always true, though. Older TCAS models are not capable of this. But they would still both issue traffic/resolution advisory.

All TCAS II systems, as used in commercial aviation, coordinate RAs. TCAS I, intended for GA use, doesn't produce RAs at all. Perhaps very early versions of TCAS II produced uncoordinated RAs but such versions aren't usable any more, so they aren't what you'd expect to find in a PMDG sim.

Was about to correct the same. Thanks.