hello, I have a 10’ copter which I use for my experiments (allows to put more stuff on it 
), it was flying quite good as for me after I did initial setup and tuning along with adding some notch filtering + autotune.
But after some time it started to behave erratically, it usually happens when I want to level copter after e.g. flying forward in AltHold. Once I bring pitch stick to the middle position after flying forward it often starts to overshoot, similar to what would happen e.g. when flying in Loiter with GPS and you suddenly stop, with exception that it also oscillates couple of times, and of course in case of alt hold I do not expect this to happen at all, sometimes it can also start to yaw :-/
I’ve checked that I did not change any parameters after initial successful tuning although I had a couple of crashes, so it could be that something has happened to hardware, but I would like to know what exactly.
I’ve attached a recent log file where it is quite easy to see what is happening. Mostly seen when I in AltHold, but I also tried to remove all human factor and used guided no gps mode to keep a steady pitch and it is reproduced there as well from time to time but in this case not necessarily when copter goes to pitch=0
Would be grateful if somebody could help analyze the log.
Thanks
I am using Copter 4.4.4 (can be seen from the log)