Laser is "spitting" around objects

So i have run out some slate coasters and noticed some “specks of dirt” around engravings. Tried wiping, doesn’t come off. Took a magnifying lens for a closer look - laser is leaving stray pulses around objects. Only around objects, no spits in wide blank spaces. Always near edges of text or graphics and inside objects with blank spaces in them.

Engraving is plain fill, not photo, so no halftoning comes into play here. Checked previews in LB (0.9.11 and 0.9.16) - no pulses there… Engraving was run on LB 0.9.11.

The run was at 15% power, 400mmps speed and 0.1 interval.
80W CDWG tube, Zye MYJG 100W psu, RDC6442s controller.

are your cables not shielded? looks like your laser PSU is getting a signal to fire.

Its the usual setup, nothing fancy. Your usual chinese setup. It cuts fine, but only notices this spitting today. What shielding are you talking about ? Specifically signal wire between PSU and controller ?

Yes, the wire between PSU and Controller, i use a shieldet.

Made up a test pattern to see if it replicated the problem - it does…
50mm circle with outlines 5mm in and 1mm thick.
Spit occurs where most switching takes place, in the horizontal axis, widest pattern, most switching there…