I have G scale track power outside. I do have stainless steel and I am DCC.
Long ago, DCC decoders would go nuts with the smallest glitch in power, resetting the microprocessor in most cases.
That was 10 years ago, modern decoders no longer have that issue, having internal 5 or 3.5 volt power supplies that are designed to keep the micro alive during short glitches.
The addition of "keep-alive" capacitor banks also help really bad power pickup issues, but I have about 40-60 locos and not one has a keep-alive.
Sounds like the RP unit is sensitive to power glitches, and forcing someone to battery is like turning the clock back 10 years in design. With the overall cost of the electronics, this is an issue that can be easily and economically solved and HAS BEEN solved with other systems.
(It still needs to be proved that the behavior here needs to be "proved" that it is coming from power glitches, maybe the voltage being higher is causing the issue, we had the similar thing in G scale where track voltage is often 24 volts and many DCC manufacturers that "came from" HO had issues with the higher voltage, like SoundTraxx)
Anyway, there is no reason to "force" someone to battery for a deficient design (to be proved).
Greg