I’ve been having similar issues. it seems some of the “proofgrade” materials have changed thicknesses, so you have to check with calipers and adjust the focus height (at least seems to be my issue) Would have been good to know before blowing through $80 of materials trying to play with settings to “fix” it. I’m beyond pissed at the moment. Instead of warning their customers or updating each QR code to set the thickness, Glowforge has said nothing and now i’m just feeding them more money. Right along the lines of the “offline mode” empty promises it seems.
Not to mention the camera calibration found here seems to require an ENTIRE piece of proofgrade medium draftboard. I’m getting closer and closer to giving up and selling this thing swapping it out for a cnc router.