If it’s doing it with Proofgrade then I don’t know what to say.
I just cut a 0.42" square from a scrap of Proofgrade clear acrylic on my 4-yr-old machine and there was no flame at all. Came out just fine, except for one edge didn’t cut all the way thru but I haven’t cleaned my optics in a few months - so I sanded that one side (furthest edge here…) That’s the “C” key on my MacBook keyboard for scale.
I test before I commit to any job, so based on this I would, for example, slow it down a little if I was using this material. Default was 125/full, so I’d probably go 115/full.
The key here is, however, there was no flame. I even took a video and there’s no point sharing it. Nothing to see.