Regarding MOTION V. 2.4.11, you’ll have to wait to see if ROBOTIS folks can help you with that issue.
In the mean time, have you tried to use TASK/MOTION V3 instead?
Also can you share more details about how you use MOTION? Do you just use MOTION directly at run time? i.e. Just use F3 to play the motion units that you created? and always in Sync mode? You can try this option in TASK/MOTION V3 instead too.
What do you mean by “Custom Speed Settings”? Done via “Edit Linked Motion Unit” - like shown below?
Or do you use a TASK code to play these MOTION UNITS? For example like shown below:
UPDATE 7/3/2025
I looks like that I also encounter some issues with MOTION 2 and MOTION 3 when using 904-C and XL-320s also! Please see my other post:
Are you getting similar issues?