How old is the radio and ESC?

I wonder if the ESC lost its calibration?

I have seen some brands of ESC's that calibrate every time you turn it on, so if you grab the transmitter and pull the trigger while it's calibrating, then that could potentially throw off the center point adjustment. I've seen some ESC's which require the trim to be set perfectly at zero no matter what. I've seen some folks adjust the spring tension too soft and the trigger doesn't properly return to perfect center which threw off the calibration as well.

I once had a friend who owned a Spektrum radio that would inadvertently reset the trim settings on all model memories no matter which memory he had selected. It didn't do this all the time, but he was able to reproduce it. The workaround was to make sure and boot the radio before making any trim setting changes so not to risk "contaminating" the previous model memory that was selected. He was getting brown outs after setting the EPA and then loosing the EPA settings between model memories, talk about a nightmare. At first he thought he had a bad ESC, but the problem persisted after replacing the ESC with a new one, which helped isolate the problem back to the radio losing the trim settings.