Hi,
I've encounter Wwise crashes during game shutdown (Build) in ~AkBankManager::AkBankManager() where AudioBanks are probably collected by GC and they have invalid value but not nullptr (UObjects should be hold at least by TWeakObjPtr).
I'm using Wwise integration 2019.2.1.7250 for UE4. Hope that this will help you to fix it.
Thanks!