Breakdown of correct physical laws in the fall of a moving boat

Steps to reproduce the issue
Prepare a path made of either a water channel or ice, with the end forming a cliff. Then, fall off the cliff while moving.

Expected result
Like recently updated minecarts, fall in a parabolic trajectory while maintaining speed, in accordance with real-world physics.

Actual result
The moment the boat leaves the water or ice, its velocity becomes zero and it drops straight down vertically. (This does not follow real-world physics at all.)