when the pic was taken, i had turned off the AT due to the weird acts of it, and i pushed hold as i was in a GA and vnav wouldnt hold it there. Im in the middle of another flight now and all is fine atm, but at the start it was doing the up and down, and i noticed that the FD's would move up, then a few seconds later, the plane would follow, but by the time the plane had got to the correct envelope, the FD's had gone down to level, causing the plane to do a big dip, then due to that, the FD's shot up, followed by thr plane a few seconds later etc etc