Hi, I’m quite a beginner flying the A320 Neo but having the same problem in the FBW and standard version. In the FBW I loaded the flight plan via Simbrief and in standard version via world map and MCDU.
When I take off and arm autopilot and in NAV mode, auto throttle and managed altitude it starts going towards my first waypoint but shortly after banks right and just keeps going around and then over speeds. I’m sure I’m doing something silly but any help would be much appreciated.
Do you have the throttles in the “Climb” detent?
The autothrottle will not work unless they are.
As far as the bank is concerned, have you set an appropriate deadzone in your controller?
I had the same problem and the deadzone got me sorted out.
Yes my throttle is in climb detent and autopilot is enabled but each time I’m heading to the transition waypoint and all goes mad and plane banks right and start losing altitude and thus is all whilst in autopilot so very strange.
I don’t know if it’s to do with me changing the managed altitude with constraints on maybe?
As MSFSFreak2019 said, in many cases, it’s joystick calibration issue. You can increase the dead zone of your stick or simply disconnect it from your computer and then reconnect them as I do.
I have a Hotas warthog joystick and throttle but have not actually used them whilst flying these times and just been using the Xbox controller to get 1,000 feet above the runway and then hit autopilot.
Unfortunately, I don’t know about xbox game pads. If you can recalibrate them, hope you try it. Even unnoticeable tiny input could override AP from my case.
I’m not 100% certain, but you should be able to set up a deadzone in the game pad as well.
Yes, you can set up a deadzone in a game pad.
If you have the joystick and the throttle plugged in, that may be your issue as well.
Try unplugging them.
No, changing the constraints shouldn’t cause this.
I will have a look but how could dead zones be the culprit when I’m in autopilot NAV mode and not even touching the controller? Did this happen to you?
Thanks for your help by the way
Ok thanks and I’ll unplug them both just to see, thanks a lot.
When a controller is released, it often (even when new) does not return to “0”.
This causes a small signal to be sent to the sim which confuses the autopilot, and what you are experiencing is the result.
Putting a deadzone in eliminates that signal.
Yes. Same problem.
Ok I’m having the same problem with the joystick and throttle disconnected so will change the dead zone on the controller and would it be just for the left stick and is 5% enough would you think?
He said FBW and Standard version. So it’s not only about the FBW 
I see that also buy hey Ho )
I’m going to quickly try the same flight on my series x as I already have dead zones setup on the controller first and if that works at least I can use the same settings on pc. I was going to have a whole day flying today after studying videos yesterday but alas 
He’ll have to troubleshoot the problem one forum at a time. FBW here, stock elsewhere. Can’t mix and match.
It’s fine and no big issue and plenty of help here 