Not sure if this is really a bug, but I copied an old save from version 3.8 to the current build (4.0), and initiated a battle with the Bandit Guard, and my companion only grew me until the game crashed...no other attacks for me or the enemy even showed. Here's what it says:
The UE4-GrowthRPG Game has crashed and will close
Assertion failed: GetFName() = = NAME_None[File:D:/Build/++/UE4/Sync/Engine/Source/Runtime?CoreUObject/Private/UObject/UObjectBase.cpp] [Line: 130]