Which reminds me I have to test my game with the new version of PowerQuest in a more recent version of Unity. I think I still have that weird crash due to save/loads. I know it use due to .NET 4 API - as when I used the old .NET 2.5 API it runs fine.
That could be it - it is very random and it is hard to debug - but all I know it is something to do with coroutines if I remember.
Going through old messages it was this:
Assertion failed: Assertion failed on expression: 'coroutine->m_RefCount > 0'
Assertion failed: Assertion failed on expression: 'coroutine->m_CoroutineEnumeratorGCHandle.HasTarget()'