To reproduce:
1. Open users attached project "DestroyEntityBug.zip"
2. Open "SampleScene.unity" scene
3. Enter play mode
4. Observe the console and look for nativeArray R results (the value should be big e.g. 28000+) it should be a lot slower than array R
5. Build for iOS
6. Observe as the nativeArray R ElapsedTicks are really small, smaller than array R

Expected result: nativeArray R ElapsedTicks is bigger than array R
Actual result:nativeArray R value is a lot smaller than array R

Reproduced on:
2018.1.0f1 2018.2.0b9

Notes:
Getting staging packages errors on 2018.3.0a2, can't build
On 2017.4 and earlier versions getting: Assembly has reference to non-existent assembly 'Unity.Entities' (Assets/Tests/Tests.asmdef) errors, can't build

Devices tested on:
iPhone 8 iOS 11.0
iPad 2 iOS 8.1.2

Expected results on:
iMac MacOS 10.13.5
Samsung Galaxy S9, OS: 8.0.0, CPU: arm64-v8a, GPU: Mali-G72