Will Open Level make game lag?

Hi,
I created a game with many “levels”. I need to use open level to travel among them. Every time i just use “open level” in my blue print. And then after I open few levels the game become lagging. I don’t know whether the lagging is related to this. Can some one give some suggestions? Btw the game is for mobile. It lags on the phone (iPhone 6 plus)

Thanks

Of course the game will lag if you open a level!
The engine has to load the geometry, the actors, the materials, etc.
There is no way around this except removing objects from the level or switching to a platform with more power.