Oh right, masking doesn’t do well with vary power/3d engrave. The issue is that the masking eats up the laser energy for the lower end of the power scale. You can offset that by using the minimum power setting, but tbh it doesn’t work too well. My best suggestion is not to mask fine engraves like that. There are several techniques for cleaning unwanted smoke marks from engraves, that’s what I’d be doing. and have done:
You can get definitely good results this way.
@shogun and I worked together before he had his Glowforge, and all of these were done on maple hardwood and unmasked, then cleaned.