It is not hinged.
Thanks for the image reference, I added this one to the document.
"Hinge joint" is a Physics rigid-body term.... it simply means it's "motion constrained to a single axis", but also does imply that it has constraints (maximum angle).
The docs seem to indicate that the dish itself has a 360 span... and the armature 180 deg. These aren't technically "hinges" though as we traditionally think of hinges.
The first two oscillilations "bounce" off something (as it's immediate and with similar rebound velocity) -- I was calling these "Hinge constraints".
In your current explanation, you are calling them "servo-motor maneuvers"...
You can modify your explanation as many times as you want, without shame. (I won't accuse you of moving goal posts, or making-up-new-shit, etc -- as this is the whole point of this process, to help devise the very best TD explanation for this behavior... which takes iterations.)
I'll document whatever you come up with... hopefully as a collaboration among the group of you.