Magnepan MMG, panel odor

[kalali]

I lent my MMGs to my brother in law over weekend and he called me and tells me he's getting an odor from the panels. He says its not a burning smell but an odor nonetheless. Here's what worries me; he was driving them with an Accurus amp that is 8 ohms and is clearly underpowered. He said the amp got very hot before he turned it off. According to him, the speakers sound fine but the odor is still there. Is it possible that the speakers are permanently damaged or its just the odor from the mylar that got warm and it'll be fine. Anyone heard this before?