Animated door not working since Unity 4.0 upgrade

I am working on a platformer and I have this door which opens via an animation trigger by a sphere collider when the player runs past, to create an obstacle in his path. There’s also a non-player character running ahead of the player who uses the same trigger to jump over the obstacle. Everything was working fine before the Unity 4.0 beta upgrade. After I upgraded, this is the only asset that doesn’t seem to work properly.
Now the first time that the door appears everything works well, however when another instance appears, the trigger refuses to work (no collision/trigger event is being called) and the door animation doesn’t seem to play. However, the non-player character, apart from not jumping over the door as he is supposed to when hitting the trigger, he stops against where the door should be in the opened state, even though the door’s closed and there’s absolutely nothing in his path.
I know this is a beta version, and it could simply be a bug. I was just curious as to whether anybody else has similar problems?

I finally found a solution. I actually had to remove the rigidbody from the door and everything worked fine again. It’s strange because in Unity 3 the rigidbody didn’t give any problems at all. Oh well, what’s important is that it works and I can move on, but I still wonder why this happened… Seems like rigidbodies aren’t too fond of animations.