Troubles with transmitter aileron "jumping" to zero

[fm4work+2025@gmail.com]

Hi all!

I recently bought a XK X6 Transmitter. Seems like the Aileron "sometimes" goes to 0 when moving the Elevator Stick towards Zero and stays stuck on Zero.
This unexpected behaviour of course crashed my Heli. Bouncing the stick brings the Aileron back to middle (50)
I suppose this is not normal - any ideas what to do about it?

Any hints welcome!
Thanks