How to reproduce:
1. Open the attached project ("case_1118527-Divinoids_For_Report")
2. Open the repro scene ("Main Menu")
3. Enter Play Mode
4. Inspect the console - notice that there are no errors regarding missing references
5. Exit the Play Mode and build the project
6. Enter Play Mode and inspect the console again (if nothing has changed, build the project again)

Expected result: References remain unchanged
Actual result: Some of the references are missing

Reproducible with: 2018.3.0a6, 2018.3.5f1, 2019.1.0b3, 2019.2.0a4
Not reproducible with: 2017.4.20f1, 2018.3.0a5

Notes:
1. The issue reproduces about 1/3 times

Fixed in: 2018.3.8f1, 2019.1.0b5, 2019.2.0a7