Error: WB_DebugSettings_C failed to
route PostInitProperties. Call
Super::PostInitProperties() in
WB_DebugSettings_C::PostInitProperties().
This error occurs always when you forget to call overridden function on Super (base class) while overriding an essential UE4 function. In your scenario, error communicates that PostInitProperties on WB_DebugSettings is not calling Super. As you say, this is a BP only project, you probably didn’t have a chance to override PostInitProperties (I might be wrong). Nevertheless, try to check overridden functions on this widget, be sure you call parent functions, check the construction script if it doesn’t generate problems. Maybe start from disconnecting this widget from the build to try if that’s the only blocking issue in your project.
The real problem is that this error is pretty low level, from callstack you can see it’s not even inside any blueprint initialization/code. It occurs immediately after constructing the object from C++, after loading the object properties. Well, without fixing the actual problem of not calling the Super, we won’t be able to guess what is really causing it.