Reproduction steps:
1. Open the "*****-client-2018-11-14" project from the attached link "oc.unity3d.com".
2. Build and run it to an iOS device.
3. Wait for the application to load.
4. Interact with the UI a little bit by clicking random buttons (i.e. click "okay" > present box button > paintbrush button).
5. Swipe with three fingers.
- The console will open.
6. Enter "force-restart".

Actual behavior:
- Crash.
- Reproduction rate is about ~30% for me.
- If the application doesn't crash, try to repeat steps 4-6 and try different UI buttons (step 4) and timings.

Call stack:
thread #25, name = 'BackgroundWorker', stop reason = EXC_BAD_ACCESS (code=1, address=0xffffffff00000000)
frame #0: 0xffffffff00000000
* frame #1: 0x0000000101965aa4 *`::Job_ExecuteUnityWebRequest() at UnityWebRequestProto.h:226 [opt]
frame #2: 0x0000000101344804 *`::Exec() [inlined] ExecuteJobFunc at JobQueue.cpp:427 [opt]
frame #3: 0x00000001013447f0 *`::Exec() at JobQueue.cpp:505 [opt]
frame #4: 0x0000000101344758 *`::Steal() at JobQueue.cpp:641 [opt]
frame #5: 0x0000000101344b60 *`::ExecuteJobFromQueue() at JobQueue.cpp:839 [opt]
frame #6: 0x0000000101344c5c *`::ProcessJobs() at JobQueue.cpp:897 [opt]
frame #7: 0x0000000101344214 *`::WorkLoop() at JobQueue.cpp:967 [opt]
frame #8: 0x000000010147d398 *`::RunThreadWrapper() at Thread.cpp:42 [opt]
frame #9: 0x00000001db2c72ac libsystem_pthread.dylib`_pthread_body + 128
frame #10: 0x00000001db2c720c libsystem_pthread.dylib`_pthread_start + 48
frame #11: 0x00000001db2cacf4 libsystem_pthread.dylib`thread_start + 4

Reproduced with:
2018.2.1f1, 2018.2.18f1
iPhone X iOS 12.1, iPad Pro 10.5" 2017 iOS 10.3.2, iPad Mini 3 iOS 10.3.2

Note:
- The project works only with 2018.2 versions of Unity.
- The project doesn't build to Android platforms.