I use some really old analog CH pedals through a USB adaptor and often have calibration issues. Sometimes part way through a flight too. Either the pedals will lock full over to one side, sometimes while taking off and sometimes part way through a flight, or they will only move one way, which I usually notice when I cannot recover from a spin.
My issues are a result of computer "issues", I've had to recalibrate in windows game controllers often recently, or, somehow, the "range" of inputs in game change for me. The calibration range of numbers switch from 0 - 31000 to 0 - 64000 for some reason and I need to recalibrate in game.
heya wrongway, if your cal range is shifting like you posted, have you took the bottom plate off your rudder pedals and checked the spade connectors to see if they were loose?
back when I had my old gameport/analog type CH stick/throttle/pedals I found that almost every connection to the potentiometers? were very loose....and was causing spiking and losing cal.
I took some wire crimpers and crimped down on each connection .making them very secure/snug...... it was a difference of night & day..was almost like new again by this simple fix........ what I thought was my controllers going bad was just loose connections from many years of use....
just saying....hope this might help..... goodluck