Ender Pearling through a nether portal in the over-world tp's you to the portals nether coordinates but in the overworld

What i expected to happen was nothing as usual when throwing ender pearls into the Nether portal

What really happened was I got teleported in the overworld to that portal's Nether coordinates

This bug seems to not exist on worlds created in 1.9 but only in worlds created before, i tried on a world created in 1.8.3 and 1.8.8 and the bug happens, so to re-create you would have to create a world in 1.8 or below and then play it on 15w34b, build a nether portal and throw an ender pearl into it. Happens regardless of what version the world is generated.

Very finicky. For me, only happened when standing one block next to (but not inside) the portal, and throwing to a spot just one block on the other side. But not always. – Sealbudsman

See this comment by [Mod] md_5 for suggested fix based on 1.10 MCP