almost all shirts in the character creator turn brown when equipped

this has been happening for a while now. it's been getting on my nerves, but usually i just wear a shirt that doesn't change colour. it seems to happen to shirts that are one solid colour. the hair i have equipped is also the colour brown, so that may have something to do with it. i've tried changing the hair colour and restarting minecraft, which i thought would fix the problem but made no difference. it's not an urgent/game-breaking problem, but surely this isn't normal??