Horizontal tail stabilizer failure in all models only with autopilot ON

[pablofercastro 0]

 

Good morning.
I don't know what's happening lately that from the A318 to the A330, with all models the tail stabilizer goes up and down continuously and the plane looks like a crazy horse.

Surely I have touched something and I don't know what. I tested the center of gravity of the planes at UP/0.8 up to 4.0 and also tried setting the values to negative. The fact is that if I disconnect the autopilot and fly manually everything goes perfectly and you can see how the wheels on the center console move freely. What I can do? Thank you so much.