My Terraria running in slow motion on a specific part of the map, close to my house. When I am in this part the game is slow, when I am not the game is normal. I play on the computer, on the Steam platform.
Do you have frame skip off in the settings? It looks to me like you’re switching biomes at that spot, which can be pretty demanding and slow down the game if frame skip is off/cause a lot of lost frames of frame skip is on.