The buggy seems to almost hit a wall when it first drives into the bump and loses momentum.
It is possible to wiggle the buggy off the bump by turning the wheels and alternating forward and reverse.
Buggy speed immediately dies when it hits the bump and becomes stuck on the bump's crest.
The buggy is able to successfully drive over the bump.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-34667 in the post.