I have found a mistake in the plastic texture pack on Minecraft pocket edition

Apparently there's an issue with the "Grass" texture (extra white pixels above the grass itself), but only when held though.

yes and iron too

Looks like this is fixed in 1.0.4.11. If you are still experiencing this issue, try reinstalling the game. (backup your worlds first) If the problem is still there after doing this, let me know and the issue will be reopened.