You are assuming that SomeMatinee->MatineeControllerName is set as “FLWeather” and that WeatherName is set as"FLWeather" but I don’t see you logging their values anywhere to really check that.
Just putting the following lines right BEFORE the “if” will tell you that:
UE_LOG(LogWeather, Log, TEXT("MatineeControllerName is %s"), *SomeMatinee->MatineeControllerName);
UE_LOG(LogWeather, Log, TEXT("WeatherName is %s"), *WeatherName);