To reproduce:
1. Open attached project;
2. Open "BugTest" scene;
3. Enter Play mode;
4. Press "Open" button;
-Notice both doors (SlideDoorLeaf(1) and SlideDoorLeaf) are opening.
5. Press "Close" button;
-Notice only SlideDoorLeaf(1) is closing.
Note: If you move a ship (using WASD) near the SlideDoorLeaf, it will close.
6. Exit Play mode;
7. Change the Scale of SlideDoorLeaf on Y axis to 1.5 or more;
8. Repeat 3-5 steps.

Expected result: Object with a smaller scale than 1.5 will move when reversing speed of Slider Joint 2D motor.
Actual result: Object with a smaller scale than 1.5 doesn't move when reversing speed of Slider Joint 2D motor.

Reproduced on versions: 5.5.4p1, 5.6.2p1, 2017.1.0f2, 2017.2.0b1.