I believe this issue is new to 1.8.1-pre3, although it might have been in an earlier pre-release build. It definitely wasn't in 1.8.0.

When we travel through a nether portal, either to the nether or returning to the overworld, our coordinates are off-set by 4-5 blocks in one direction. This can end up placing us inside blocks and causing damage.

I can provide screenshots later if needed, or any other information. It seemed to affect everyone who attempted it, and occurred on multiple portals in different locations.