I haven’t heard anything about that… I would assume the worst thing is that because the filaments are meant to melt at fairly low temps, you’ll end up burning some of it even if you added metal or glass downstems and bowls to it, since those materials could transfer the heat to the main body.

I have had that experience with cheap plastic bongs that weren’t even 3D printed. I would just stick to glass, metal or silicone.