Can you also share what your VS was before you leveled off?
I have the same issue with the 777, ignored it at first when cruising at 34,000 ft @ Mach 0.85. Step climbed to 36,000ft 5hrs into the flight, still the same bobbing effect. I’ve tried to manually fly the plane and maintaining 0 v/s @ that flight level, but the moment you activate altitude hold it bobs.
I was cruising at 35,000 at Mach .85 and it happened but continued to get worse
Speeds for the A319 are around Mach 0.75-0.77 (someone correct me if I’m wrong).
I think you’re going well above the speed for your aircraft. THat’s probably the issue.
I was traveling in a 777-300er
My apologies. Still that seems a bit fast for the B777 but I don’t fly it as much so who am I to know :)
This isnt an issue with global as I have experienced this same problem with the pre global build. Like said above, your speed and climb profile is most like the culprit, I usually climb through FL280 at 300KIAS which becomes M.80 and that usually works out well for me. If you are experiencing the bobbing issue after climbing, I usually just stabilize the aircraft manually and that works out well for me.