I've never noticed the shirt problem before, so now when ever I watch the films I'll notice it and be annoyed by it :P
One thing that I always notice is that before Han gets frozen, his hands are hand-cuffed, but when we see him in the Caronite, his hands are up. Is he Houdini breaking out of hand-cuffs? Or did the Carbon thing melt the hand-cuffs, if it did that, wouldn't Han die from the heat? Or how about I just shut-up because it's a film :P