With collisions enabled for scene and ground, if you move the character mesh using moveWithCollsions(), the character stops moving after a while. I have seen this again and again and others have reported it too. Sometime, the character moves up the ground quite a bit. Here is a playground example to see this:
Move the character using WSAD keys for a minute. You will see that the character stops moving or goes sideways when it is supposed to go forward. I looked at the current implementation of moveWithCollision() and DefaultCollisionCoordinator and I have doubts on some part of this piece of code and I think it needs some rework. But wondering if there is another CollisionCoordinator someone might have written.