I have measured the board in question and it came out 3.4mm thick. Measuring another draftboard, it was 3.3mm. Then I measured a piece of medium basswood plywood included int he starter kit and it was 3.4mm.
For the heck of it, I put the thinner board into my Glowforge and tried to print a reset design of the GOGM. It once again failed to cut through just now (roughly 10:30 pm Central time). If I hold that board up to the light, I can see 5 tiny dots on the back side, seemingly where the laser attempted to cut through on each circle and failed.
I then put the original board back in and tried a different design - just a blank pico 12 piece puzzle design. That cut through entirely, leaving only a bit of the bottom side paper uncut.
It seems to be some designs, but not others, and that gives me reason for concern, as an intermittent issue is really an issue when you have material costs for oopsie cuts andonly a six month warranty on the laser tube.
Before cutting tonight, I once again checked my optics… all clean, no scratches or smudges. I welcome your advice.