When are hit by something like a player or any hostile mobs, you're tamed Wolves won't attack them. They will only attack them if you attack what's attacking you.
MCPE-9165
Tamed Wolves aren't provoked when players are hit
Resolved
Duplicate
0
(Unassigned)
Unconfirmed
Phone - Android - Samsung Galaxy S5
Android 5.0
0.11.1
Retrieved
This is true sometimes, it goes on and off for me, they seem to only get provoked if they can see me, but if they are in grass or behind a block, they ignore me being damaged.