Upstream has released updates that appear to apply compile correctly.
This update has not been tested by PaperMC and as with ANY update, please do your own testing.
Bukkit Changes:
d2834556 SPIGOT-4219: Event for PigZombies angering.
CraftBukkit Changes:
a9c796f1 SPIGOT-4184: Fix furnaces not matching Vanilla smelt or animations
195f071e SPIGOT-4219: Event for PigZombies angering.
5e3082c7 SPIGOT-4230: Improve legacy block types
Fixes GH-1295
Non-standard sized portals exacerbate a flaw in the vanilla
portal teleportation adjustment logic.
As a result, an entity can end up slightly inside of the surrounding
portal blocks. In vanilla, this issue is minor and you are adjusted out
as if it never happened. In CraftBukkit and derivatives, the
anti-suffocation behavior activates and players end up teleported on top
of their portals.
This improves the offset so as to keep the issue from ever occurring in
the first place.
Special thanks to CarpetMod who appears to have had this fixed for some
time, and has licensed their code such that we can use it as needed.
Aikar
Zach Brown