Steps to repro:

1. Open Unity on OSX 10.11;
2. Create new project and scene;
3. Modify scene (e.g. add some gameobjects);
4. Open Asset Store (Window -> Asset Store);
5. Import any project containing a scene (e.g. 'SpringPong');
6. In the Project folder navigate to any scene that is inside the downloaded package;
7. Double click on this scene to open it;
8. In the opened dialog window click 'Save' button;
9. Observe the console.

Actual result:

Weird allocation errors appear in the console:
- "TLS Allocator ALLOC_TEMP_THREAD, underlying allocator ALLOC_TEMP_THREAD has unfreed allocations";
- "Allocation of 1 bytes at 12911030"

See attached gif video and actual.png screenshot.

This bug is probably related to partial fix of the case 753114 - http://fogbugz.unity3d.com/default.asp?753114&smv=1&be=dk

Regression introduced in Unity 5.3.2f1.

Expected result:
Errors should not appear after clicking 'Save' button while switching to imported scene.

Notes:
- Reproducible in: 5.4.0b13, 5.4.0b12, 5.3.4p1, 5.3.3f1, 5.3.2f1;
- Doesn't reproduce in 5.3.1f1;
- Reproducible only on OSX El Capitan (10.11.1). Doesn't happen on OSX 10.10;
- Doesn't repro on Windows 10.