Automatic Transmission Issues

I have an Infiniti G20 that is having problems with reverse. I thought the transmission was bad so put in another used one. End up driving it 20-25 miles then reverse goes out.

Fluid looks great. All other gears work fine… it’s almost like it’s stuck with neutral and reverse. It can’t be a coincidence that this happens on multiple transmissions.

Could this be symptoms of a bad Torque Converter Inhibitor Relay?