Foxmoth,
If TCAS was not working or properly functioning on RA65816, then I believe no RA conclusion on board of 757 occurred considering the way TCAS II works. It could only receive traffic warning in that case, in other hands considering you’re listening comm. frequency you won’t be dive beeing aware there is another instructed for immediate descend. We should wait for tapes, fully agree here, but it really looks like Russian pilot has failed to follow RA command and commenced ATC instruction.