Personally, I think it looks great with the gray tinge to it. IMHO.
I don’t know what brand inventables resells, but here’s a fabrication document for King products. They sell a product called Colorcore, which is a 2 color poly product. Not marketed as laserable, and no fabrication techniques in their fab guide. Called my vendor and they have in their sales notes that the product isn’t laserable. Guessing your grey is melt.
Secondary issue - burning plastics often results in all kinds of toxins being emitted. Yes, people laser acrylic all the time - the fact that everyone else is doing it doesn’t mitigate the risk though. More of an FYI than anything, but since I’m already typing…