Physics object resting on movable platforms have erratic physics behavior in 4.14.

This is a regression from 4.13.2-3172292

User Description:

When placing more than 10 or 20 blocks on a moving platform, the blocks will not stay nicely still on the platform.
They 'jitter' and eventually slide off the rear end of the platform.

This can be reproduced by creating a new project, create a blueprint with a moving platform(cube) using the 'move component to' function, or any other way to move it (horizontally). Then place some cubes on it.

In UE 4.13 everything works fine. I have noticed the issue in both 4.14.0 and 4.14.1.

Changing physics sleep settings and sensitivity on the blocks and the platform does not appear to influence the issue.

Steps to Reproduce

1. Open the attached 4.14 project
2. Simulate

Results: The boxes will fall onto the moving platform and stay nearly in place until they fall off.

Expected: For the boxes to stay on the platform with realistic physics like in 4.13.2.

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ComponentUE - Simulation - Physics
Affects Versions4.
Target Fix4.17
Fix Commit3488178
Main Commit3502661
Release Commit3273224
CreatedDec 14, 2016
ResolvedJun 13, 2017
UpdatedApr 27, 2018