Recently noticed that some ai aircraft particularly all FAIB models fluctuate in pitch and climb rate just after liftoff which is odd looking, as though trying to compensate for excessive climb rate. I do not remember or rarely seeing this before. AIA and TFS models appear to have a better FDE in this regard with a stable maintained pitch and climb rate after takeoff. I have tried to compare major fde parameters between the two to figure out any problem variables but so far haven't been able to find out anything useful with most variables having similar values. Has any one else looked into this and found more info on the causing parameters?