The screen randomly freezes when we first switch to a item in hotbar like blocks or tools, because it's set to strictly re-calculate the models and vibrant effects first,The ram quickly fills up and the game freezes completely for 4 or 5 seconds even on high-end devices,
Though i normally get 60+ fps when playing (with Vibrant Visuals).
Also once this has happened ,it doesn't happen again for around two minutes, as if it’s cached in memory.