Standalone player crashes half of the time. Editor reported to crash too but couldn't reproduce on mac.

How to reproduce:
1. Build standalone player
2. Run the game and go to the far pillar
3. A bundle starts loading asynchronously
4. Game crashes:

Receiving unhandled NULL exception
Obtained 8 stack frames.
#0 0x00000000a3a115 in PersistentManager::LoadObjectsThreaded(int, int, LoadProgress&)
#1 0x000000009bb4e5 in LoadOperation::Perform()
#2 0x0000000099999c in PreloadManager::Run()
#3 0x000000009998e1 in PreloadManager::Run(void)
#4 0x00000000a7a051 in Thread::RunThreadWrapper(void*)
#5 0x0000009a5a6794 in _pthread_body
#6 0x0000009a5a670a in _pthread_body
#7 0x0000009a5a3fa6 in thread_start

Tested with 5.2.2 and 5.3.0f2.