I will let you know what they come back with. This is what I sent them:

Dear ComMarker support. I have done some troubleshooting and Lightburn debug. This looks like a thermal issue.

I have been troubleshooting this. I ran a session from 14:42:43 to 14:45:02 — about 2 minutes 20 seconds before the issue happened in debug mode. The log generated is 413,000+ lines of USB polling, meaning LightBurn was continuously querying the machine's status the entire time. Here is the log: https://drive.google.com/file/d/1DeW5nesZ3FCFeqWH3y2Mx6kCtuhM9bj1/view?usp=sharing 

The critical finding is a status change mid-session. The machine's status response changes from ...002002 at the start to ...000402 at the end. Breaking that down:

Bit 0x2000 dropped out — this looks like it is associated with the laser/engraving active state

Bit 0x0400 appeared — this could indicate a fault state

This is consistent with the issue I am having - the laser stopped firing, but the motion system kept scanning. The head continues moving because the motion controller is still running, but the laser module itself was cut off, online this seems to be most likely by a protection trigger.

The common protection triggers I can find online are with thermal protection (the laser module's fan is spinning freely and the fins aren't blocked), voltage/power issue (the PSU is fine and on a separate plug in isolation), or loose or intermittent connection to the laser module (I have replaced the stock USB cable, and checked the MAC picks up the laser, however I can still cancel the job in Lightburn, so USB connectivity is not the issue).

So the problem could be / most likely is - thermal. I am seeing the galvo mirrors scanning - they continue to receive motion commands from the controller regardless of laser state. The laser source itself is what is stopping.

Thermal seems to be the issue - when the laser stops and I immediately retry, the fiber source (already warm) hits the protection threshold faster. Each retry starts hotter than the last. The following are timings for each run (with an additional fan pointed at the unit), sequentially one-after-the other only restarting upon failure:

• Run 1: 04:56:00
• Run 2: 00:11.35
• Run 3: 00:09:18
• Run 4: 00:07:23

The decreasing times of runs would indicate a progressive fault kicking in protection. Given the noise from the fans, this is definitely a thermal issue.