"He who marches out of step hears another drum." ~ Ken Kesey
Starting last year, we have seen unbelievable problems with discoloration & scorching with NL shirts, both triblends & poly/cotton blends. It seems they can't completely tolerate the temps that plastisol cures at, and certainly not much higher. If I temped shirts (with a gun) at 340+, we were pretty much assured to have problems... but lower temps didn't guarantee we were safe. I now never suggest NL, and try to steer customers to other brands. If I have to print them, I'll use low cure inks - preferably One Stroke's ELT series, since it can cure in the 270-280 range. That way, even if we peak around 300, we're much more likely to avoid problems. (FWIW, I like the ELT-S inks, especially on triblend - the "S" is for stretch additive, and they do indeed stretch & flex pretty well.) We also cure the shirts full length, as flat as possible - they like to discolor on the peaks of wrinkles, and if you fold them over, you may end up with the top half a different shade than the bottom half. (I don't think we've seen those problems with ELT ink, but the shirts cost us a lot of money in replacements last year, so we haven't quit the precautions yet.)
...my only issue at the moment is fiber mat down...