A known issue is tightness of the spool in the arm which can get worse over time.
A couple of questions,
What Retraction force are you using? (see Setup then Config)
Is it Maslow 4.1? or the earlier 4.0?
Sorry it’s taken so long to get back to you. I recently had a problem with a damaged spool jamming, some of the teeth were bent and it was jamming, unpredictably. I replaced the spool.
I think it is important to smooth the spool bearing surfaces, so the spools rotate easily. Since I have done this, I am able to reliably retract with only 600 Retraction force.