Confirmed. This bug happens with any entity while the player is riding it.
"/xp 1 @a" experiences the same failure.
The command will run with non-integer values, but it rounds them off. This makes pitch-shifting granular only to the octave.
Yes, I was just giving an easy repro.
You can force this to happen by switching to or from an item that modifies the same attribute in your hand.
No, this was resolved almost immediately.
No, it appears to be fixed.
As of 13w05b, this is now an extremely common issue.
Using a Silk Touch shovel on ice works, why wouldn't using a silk touch shovel on web? As far as I know, the shovel is not the correct tool for either material.
Confirmed. It appears they only get north and west velocity when they come out of the dispenser.
Confirmed. Happens in a hallway as well.
Confirmed.