How to reproduce:
1. Open the attached 'BoatyMcBoatFace2018.zip' project using the EnvIronman VM (optional) (more information in Edit)
2. In the Hierarchy window select 'Boat_Export' > 'RearSail'
3. In the Inspector window select 'Edit cloth constraints'
4. In the Scene window observe Cloth Constraints on 'RearSail' object
5. Open the same project with 2019.1.0a12 (or later)
6. Repeat steps 2-4

Expected result: cloth constraints remains the same
Actual result: cloth constraints are scattered

Reproducible with: 2019.1.0a12, 2019.1.14f1, 2019.2.2f1, 2019.3.0a12, 2020.1.0a1
Not reproducible with: 2018.4.7f1, 2019.1.0a1, 2019.1.0a11
Could not test with: 2017.4.32f1 due to missing prefabs

Note:
1) Upgrading to 2019.1.0a10 (does not scatter the constraints) and then upgrading to 2019.1.0a11 scatters the constraints
2) Only reproducible with the user's provided project and objects that have the constraints