Steps to reproduce:
1. Switch the platform to iOS
2. On the toolbar, press "BossAlien/Utilities/Cache Clearing/Clear ALL"
3. Launch in editor from scene "Splash"
4. Enter the garage (Home Screen)
5. Tap Rare Imports
6. Wait idle on the rare imports screen for 5-10 minutes
7. Tap back to return to the garage
8. Repeat from step 5

Result: Editor crashes.

Stack Trace:
#0 0x000001017cc9e0 in Unity::Component::CheckConsistency()
#1 0x00000101adfabe in Renderer::CheckConsistency()
#2 0x0000010209738a in AwakeFromLoadQueue::InvokePersistentManagerAwake(AwakeFromLoadQueue::Item*, unsigned int, AwakeFromLoadMode)

Note: reproduction time varies and can easily take more than 30 minutes.

Reproduced with: 5.6.3f1, 5.6.2p4, 5.6.1f1.
Not reproduced with: 2017.1.0p2 (due to Errors in the Console).

Reproduces on macOS and Windows.