Again, proper training (in this case, limitations of the resolution of the TCAS display) and oversight would help eliminate this type of problem.
OTOH, as in the personal incident I described earlier, ATC can make bad calls (reversal of turn) as well. So, ANY time there is a TA that looks to the Pilot to be an imminent RA, the Pilot MUST:
Prepare to respond to an RA
Query ATC as to whether they have the traffic and are aware of the conflict. For example: "Center, ABC123, I have a TCAS TA for co-altitude traffic 20 miles ahead. Do you have them?"