Reproduction steps:
1. Open the attached project;
2. Open the scene "ReproScene";
3. Click on the object "Unlocked object" and click "Toggle locked state" button;
4. Reopen the scene "ReproScene";

Actual result: the dialog window "Do you want to save the changes" does not show and the state of the object is not saved.
Expected result: the dialog window should show up that the state of the object will be saved.

Reproducible with: 5.5.4p3, 5.6.3f1, 2017.1.0p4, 2017.2.0b7, 2017.3.0a4