When using the thunderbolt adapter connecting to ethernet, the cursor starts swirvling on the screen. The toudhpad will not repond to the movements and the cursor goes its own way on the screen. Only wifi works on my MacBook Air i7/256. Strange.
MacBook Air, OS X Mountain Lion (10.8.1), Thunderbolt Ethernet adapter
I had the exact same problem and unplugging the thunderbolt ethernet adaptor worked for me as well. I've been dealing with erratic cursor movement for the past several months. Restarting my computer would temporarily resolve the issue. I've tried all the other suggestions, this is the only reliable and repeatable solution to the problem.
Removing the thunderbolt ethernet adapter instantly fixed the issue for me as well. The cursor was off by ~cm on my 4k display, and the click target was off. It was difficult do adjust windows, click small targets, etc... The cursor would jump around to the correct click target and back to the ~cm off position.
I now connected my mouse, and this works just fine! It is my touchpad that goes a litte bananas when I connect the ethernet through my thunderbold ethernet adapter. Still strange.
Ethernet through thunderbolt
