Issues in minecraft snapshot 14w11b

first issue :-
mobs can't swim in snapshot 14w 11b , I saw zombies couldn't swim goodly on the water surface they were standing and wanting to attack me with very slow movements "not just zombies I saw all mobs can't move goodly on the water ".
second issue :-
and my friend was not able to break the dirt in a specific area while we were playing on snapshot server
*I don,t know if second issue is a bug or not because we was in a small island we didn't go far .
thank you for your attention (: