Hey,
This might be the same as the issue described here Two questions about CannonJSPlugin - #2 by Deltakosh, see this playground which is able to control the accuracy with the fixedTimeStep control but note if this is increased too low it might affect perf: https://www.babylonjs-playground.com/#BEFOO#362
For the other issue (edge causing too much force) would you be able to create a playground replicating the issue?