My MPR121 would keep the "touched" and "released" states when a finger is holding on a pad. And one of the electrodes even can't recover from the "touched" state sometimes.
Btw, when I have 2 fingers holding 2 electrodes, the glitch won't happen.
I used all settting in the application note AN3944.
One thing I noticed that in application note AN3747, it recommended to use thin <0.2mm traces for electrodes connections. But on my PCB I used 0.8mm traces which seems too wide. And I used 100% ground plane around the traces and the electrodes, 0.4mm gap between the traces / electrodes and the ground plane. Will this be the main cause of the problem?
Btw, I have another question, does MPR121 reset all its internal settings when rebooted? In other words, even if I really messed up the settings on the registers, when I upload a new correct one and reboot, it would recover from a "clean" state and start up with the new setting?