This got me thinking so I pulled out my Hunter to check.
Under the "List of ECU Warning Message Codes:" on pg 63 the manual says that "RC SIGNAL LOST / INCORRECT: The signal received from the RX is wrong (outside calibration margin) or absent."

I think these codes show up in the logs but I don't see them anywhere on the GSU but may be under Abn codes after a run.

I set up my throttle fail-safe outside of my learned range and when I disabled my TX the GSU said "Trim Low Th: OFF".
Next I set my throttle fail-safe to OFF and the GSU flashed between "Th: OFF" and "Th: ----"

Once the signal was restored and if in low trim, it continued to flash until the trim was raised. If it was above low trim it would continue without the flashing. Then all was normal again. So, the turbine may have gone into fail-safe in both cases or maybe just when the signal was totally lost but I think the only way to know is to dig into the logs to find the codes.