Hi Mr. Grossman
I do not have extensive experience with locking joints, ...mines are still moving smoothly in reasonable syncs. 🙂
However, I have had some problems with F360 ball joints...
Regarding the issue you are facing, it is difficult to judge without conducting spiritual excorcisms on the implementation. It would be difficult and effortful (black roster, obsidian knife, clear full moonlight, proper mushrooms, lingering hangover aftereffect, etc.) considering the meagerness of the documentation.
My guessing is that in unconstrained (un-locked) kinematics, successive nodes' (joints) states are calculated adaptively based on their last positions. In free kinematics ( like yours unconstrained-multi-joint robot arm ) there will be the infinite number of solutions to respective joint tensors, ... so a step-by-step adoption algorithm is chosen to resolve the dilemma.
The algorithm might fail when you lock-unlock joint, because of insufficient or undetermined boundary conditions.
But do not wary too much ... artificial intelligence is coming ... IT will solve such a poultry problem ... and more!
With Regards
MichaelT
MichaelT