you are overlapping all actors. so absolutely anything could end up as the 0 index in that array.
you need to be more selective with either how you filter the array, or what you allow to go into it.
You can either only allow actors of a specific type to be added to the array. Or you could search the array only for a specfic type.
My preference would be to make a custom collision channel and only have the overlap work for that channel.