While offline and playing wilderness mode (splitscreen) upon death the player has the chance to select another character and start anew on the day you died in a random location, this erases the exploration of the map, but when entering a cave previously explored, the explored area of the cave stays the same as before death.
Steps to Reproduce
Explore a cave while playing wilderness mode, die and after respawn re-enter the cave and the area previously explored should still be visible on map
Status: Known Issue
We are aware of this issue and have it logged internally but either we do not have a fix ready yet or we are not planning on addressing the issue in the immediate future.