As a follow up to my own post: I stumbled across this and it may be what’s happening to me. Doing a lot of small circles may be overloading the processor. Lets talk about ARCs and Circles - #21 by SkyKam
I’ve since done a test cut with raster instead of the spiral and still got very good results. So I’m not so concerned about this problem but it is something to be aware of. Perhaps the Onefinity needs a faster RPi.