Players traveling to the Nether spawn in at the proper location with the correct linked portal, but after moving a few blocks, they are glitched back to standing in the portal and instantly teleported back to the overworld, where the same thing happens. After moving a block or two they are glitched back to standing in the portal and instantly teleported back to the nether, endlessly on repeat.
Effects all players on my home machine hosted SMP server in both survival and creative.

The machine hosting the server is a 6-core i7 with lots of RAM, 3GB dedicated to the server. Using Java build 1.8.0_40-b25

Edit: just realized this was a repeat of an already reported bug. Didn't find it when searching the first time around. Feel free to delete this redundant report