Incomplete wood cut-through with Kern / 150w Coherent

So we’ve got this Kern with a 150w Coherent RF module, but for a reason i don’t understand it sometimes will NOT cut all the way through, even on 1/4" plywood that cuts fine on our 80w Rabbit. Bottom side shows intermittent cutting: most spots cut through, but not at normal kerf with, and with many little uncut “bridges”. Same thing when cutting 3/4" cypress: cuts 99% of the way through, but leaves little bridges in spots. I’m guessing this an optics/material issue, not anything with Lightburn.

Yes, this is the machine I’ve been working on for a year. (Ruida controller replacing 2002 Kern controller. It’s ALIVE! :smile:)