I just want to make sure we are on the same page .........................
You are talking about the bit or bit holder not seating into the chuck? As opposed to a bit not staying seated into a bit holder? Right?
Does the Festool bit stay in the chuck?
Exactly what type of bits ( ball detent, wire detent, Centrotec) are not holding in the chuck?
The collar on the chuck moves forward (away from the tool body) to release. Move the collar all the way forward, hold, insert ball detent bit, release collar.
Also-- if you just push the ball detent bit hard into the chuck it will snap into place without even needing to move the collar.
Seth