Swadge Land: Checkpoint flags unset (only visually) after they leave the screen

If a player dies and respawns at a checkpoint, or even if they walk away from it and back, the checkpoint flag will revert visually to its unset state. This could cause confusion as to whether the checkpoint was actually set, or whether it needs to be set on each revive.

Since it's only visual, it's not a high-priority bug, but it's still best to correct it if possible