Cannot access blueprint istance

Hi, I’m receving these warnings in the log, but i can’t find out what do they mean.

The warnings started to come after I made this algorithm to spawn a random actor in a certain location. The vectors are inerithed from the GameMode BluePrint and, after the set, are never modified in runtime.

I would also like to ask if this promote to variable, considering some big vectors (± 10 vectors of 50 complex Blueprint each) and a re-cast every 10 secs could be dangerous for the game performance.

Thank you.