What is happening:
There is a gap between where two peices of ground intersect that the player can see through. Further down the seem the problem is much worse as the ground humps upward. Running into this hump sends the player flying.
Steps to reproduce the issue:
At the spot marked in the screen shot in the Heartlands (toward the statue from the Midway village) there is a very clear split in the ground.
Game client version:
64-bit, Windows 10.