Reproduction steps:
1. Open the attached project.
2. Build and run it to iOS or WebGL using IL2CPP scripting backend.
3. Click 'Chat'.
4. Click 'Start Sample'
- Application will crash

...
frame #0: 0x0000000100b177f8 ProductName`::OnGameObjectChangedScene() [inlined] GetPhysicsSceneHandle2D at UnityScene.cpp:451 [opt]
frame #1: 0x0000000100b177ec ProductName`::OnGameObjectChangedScene() at UnityScene.cpp:296 [opt]
frame #2: 0x0000000100b17738 ProductName`::DontDestroyOnLoad() at SceneManager.cpp:516 [opt]
frame #3: 0x0000000100be5d18 ProductName`::Object_CUSTOM_DontDestroyOnLoad() at UnityEngineObject.bindings.gen.cpp:143 [opt]
frame #4: 0x0000000100067cd0 ProductName`::HTTPUpdateDelegator_Setup_m1738400195(__this=<unavailable>, method=<unavailable>) at Bulk_Assembly-CSharp_1.cpp:49616 [opt]
frame #5: 0x0000000100067fb4 ProductName`::HTTPUpdateDelegator_Update_m2271029028(__this=0x0000000110b482c0, method=<unavailable>) at Bulk_Assembly-CSharp_1.cpp:49728 [opt]
frame #6: 0x00000001008732f8 ProductName`RuntimeInvoker_Void_t1185182177(methodPointer=<unavailable>, methodMetadata=<unavailable>, obj=<unavailable>, args=<unavailable>)(), MethodInfo const*, void*, void**) at Il2CppInvokerTable.cpp:13492 [opt]
frame #7: 0x0000000100e209b8 ProductName`il2cpp::vm::Runtime::Invoke(MethodInfo const*, void*, void**, Il2CppException**) + 108
frame #8: 0x0000000100b92628 ProductName`::scripting_method_invoke() at ScriptingApi_Il2Cpp.cpp:242 [opt]
frame #9: 0x0000000100b966b4 ProductName`::Invoke() at ScriptingInvocation.cpp:341 [opt]
frame #10: 0x0000000100b9f84c ProductName`::CallUpdateMethod() [inlined] Invoke at ScriptingInvocation.h:70 [opt]
...

Reproduced with:
WebGL - IL2CPP
iOS - IL2CPP
macOS - IL2CPP (Crash on application launch)
2018.3.0a1

Not reproducible with:
iOS - Mono
macOS - Mono
Editor
or
2018.2.0b7

Note:
More logs attached in the edit below.