Weird Purple Door Pixels.

In this recent update (1.7) i have been getting wierd pixels when i left-click a door when it shows the little bits being destroyed it comes up with purple ones:
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Anyone else getting this? (that is if youve got 1.7(ive kept 1.6.6 and upgraded so i can still use 1.6.6))

Just think: all these new bugs just for pistons, which he very well could have just used a piston mod from someone else and just implement it in the game. Way to go, Notch.

but he cant just steal someones code, he has to write it himself and go through all of the debugging thats already been solved by other people :-p. I havent played 1.7 i was excited to until i realized adventures werent in them.