[Judge]

If the light on the RX is going red that is telling you that it has lost contact with the TX. Cycling the power resets the RX, and if it "sees" its TX, then the light turns green.

For some reason it appears that these RXs are losing contact with the TX. Since it is highly unlikely that two separate RXs with the same issue arrived in the hands of the same person, I suspect the TX.

So again, I'd check that the TX module is fully seated and that the pins look OK. If all that looks good I'd send the TX, module, and RXs in to be looked at.

I would check that the TX module is fully seated. I would also look to make sure there are no bent pins, etc. It sounds very much to me like an issue with the module, or how it is installed.