Steps to reproduce:

1) Download attached project ' ReproConstraints.zip' and open in Unity
2) Open scene 'ReproScene'
3) Select 'Cape' GameObject in the Hierarchy window
4) In the Inspector window, click on Edit Constraints(Cloth component)
5) Select Paint tool and drag mouse cursor through those constraints
Note: They will become invisible after mouse cursor reaches them

Expected result: Constraints stays visible
Actual result: Constraints disappears when mouse cursor reaches them

Reproduced with:
5.5.3p1, 5.5.3p2, 5.6.0p3, 2017.1.0b2

Not reproduced with:
5.5.1f1, 5.5.3f1

Regression from:
5.5.3p1

(Short video of reproduction is attached ' 2017-04-22-1422-05.mp4')