That is why I ditched it for BLTouch. Capacitive sensors like that are industrial systems meant to tell a machine when a relatively slow movement has reached it's end. They really aren't meant for precise repeatable readings. Slight changes on the input voltage like bed heater PWM can through them off.
So you solved your own problem! Get a BLTouch!!
I have moved to them myself, you can see it through my progression of mounts.
First I designed my own with a side mount: https://www.thingiverse.com/thing:2734717
Then center mount: https://www.thingiverse.com/thing:2766701
Then BLTouch once I learned my lesson: https://www.thingiverse.com/thing:3160905
That's my latest, also in single: https://www.thingiverse.com/thing:2873811
So yeah, switch it up and enjoy the stability!