I didn’t, sorry. Maybe the Discord can help you. I haven’t seen it be relevant anywhere else in the code I saw though and it seems to be essentially just editor-QoL anyway, so I guess it isn’t THAT bad if it can’t be figured out.
Welp I just checked that code out, looks like someone was a joker(or I’m the joker and just don’t understand why they did that) and decided to check for the ability’s own ActorInfo without providing a way to put an actor info as a parameter/take it from the ability system directly. This is bad precisely because GameplayAbilities set to non-instanced are, well, not instanced and can’t save their own ActorInfo struct to use, so the ability cries error even though there isn’t really a reason to.
Your options would be to either just set the ability to an instanced option, to implement all non-instanced abilities wishing to apply GameplayEffects in C++(because this function DOES exist, it just isn’t exposed to BP), or to expose said C++ function to BP by wrapping around it nicely with a BP-exposed helper function(and then taking the ActorInfo itself from somewhere, either the calling AbilitySystem or just constructing it yourself within the ability).