Sudden FPS drops (potential memory leak)

My game always runs at about 150 fps while in my hideout and stays at like 70-120 fps during high tier maps.

But since the last update my FPS suddenly drops from 100 fps to like 50 fps in the middle of a map or while delving and it never goes up even when there are no mobs on the screen, and it even stays at like 100 fps in hideout.

If I restart the game it goes back to normal (150 fps in my hideout), so I think it might be caused by a memory leak.


PS: I specifically encountered this problem during Delve and Harbinger memories, normal maps seem to work fine for me.