In a freshly generated 1.7.6 world, I spawned in a few player skulls with this command:

/give @p skull 1 3 {SkullOwner:Dinnerbone}

Whenever I place these, it takes about 4 seconds before I actually see a player head(the space looks empty before that), but it appears as a steve skin, and seems to stay that way.
I tried relogging, and tried multiple heads, it doesn't seem to matter.
Could this be connected to the crashes I experienced with player skulls last week?