This is what works for me with V15.01.22 and the rotary connected to the U axis.
- Enable rotary in Lightburn
- Use ‘Start from current position’ in Lightburn
- Jog x and y on the Ruida to move the laser to the required starting point on the work
- Press ‘Origin’ button on Ruida
- Send job from Lightburn to Ruida
- Run job by pressing start button on Ruida.
Step 4 is the key to success.