I knew there couldn’t be two of you! 
We moved earlier this year and … well, the plotters & supplies are unpacked on a conspicuous shelf, so that’s a start.
Agreed.
A similar case:
We didn’t find a solution, but the thrashing around may suggest a test or approach you haven’t yet tried.
It feels like an HV supply timing problem, but the fact that it isn’t handled by the timing variables LightBurn provides is worrisome. I don’t have a good model for what else it could be.