I have been doing planetary imaging on my exos2 and I experience the same rocking motion. It caught my attention when I noticed the sound of my motors had a rhythm that matched the rocking motion on the video. I am using an 8” SCT (2000mm FL) with a 2x Barlow. I also use the ASIAIR Pro.
It’s mostly evident when I go into the 320x240 ROI mode on Mars. The planet fills most of that area but the rocking motion stays confined within that view so I am able to successfully record the video I need for stacking. The planet will slowly move out of the FOV even with the mount tracking so I use the manual controls to keep it centered while recording. I just assumed that was due to my polar alignment that not being perfect.
jusr thought I would include my experience with the wobble/rocking on my mount.
Skill Level: Newbie learning astrophography
Mounts: ES EXOS2 with PMC-8
Scopes/Lenses: Canon 300mm F4, ES 10" F5 Truss Tube Dobsonian, Meade LX65 8” F10 ACF SCT
Cameras: Canon EOS 650D T4i modified, Canon EOS 750D T6i unmodified, ZWO ASI120MC-S, ASI120MM Mini
Software: ASIAIR Pro, Still Learning the Ropes :)