I'd say if you got into the stick far enough to spray the contacts an even better idea would be to disconnect the cables from the pcb and re-insert them since you have it apart already. Chances are that's really where your problem is and just spraying them will be a short term fix.
Usually these newer contractless sensors don't spike at all by their design. Nothing to wear out or get dirty as with a pot. But as they're much more sensitive than the old pots they're also much more picky about the signal from the sensor to the controller on the board. Anything less than a solid signal to the board will be translated as movement but even more so because of the sensitivity.
One thing common to all sticks regardless of sensor is that they move around a lot. There are wires or wiring harnesses that run from the gimbal to the pcb where the controller is and sometimes they can either work loose or break a wire. The wires are usually pretty small gauge so it's not unreasonable to figure after so many miles this can happen. I don't know how many times I'd gone into my old fighterstick to clean or replace a pot, but every time I did I'd always find a spade connector or two that was loose in there. I haven't had this happen to me with my VKB stick but I've seen it's happened to others on their forum. Check your wiring.
Sent from my Moto Z2 Force using Tapatalk