I made a video: https://www.youtube.com/watch?v=Z-R_HKHxE8o&feature=youtu.be
This was tested with arma3diag.exe and latest dev branch (whatever version was the latest as of 2 Oct 2017).
Vehicles come from CUP mod but as far as i can tell its replicable with all of them.
Do "EPEVehicle" diagEnable true in the debug console, drive any tracked amphibious vehicle into the water tapping left or right slightly so that the two tracks apply different force when getting into water, then try going back ashore.
As soon as you reach shallow waters the vehicle will spin out of control.