Bug with tipped arrows, arrows with potion tips do not apply effect

The arrows with tipped potion effects no longer apply desired affect when shot at mobs.
What i expected to happen: i shot a mob with a healing arrow and it gets hurt because it is undead.
What actually happened: the mob took normal damage.
Steps on replication:
1. Aquire bow, arrows with tippedances effects (specifically healing), and an undead mob (I shot a pigman)
2. Shoot mob with said bow and arrows.
3. Observe bug.