The box in Silverpine Forest will always despawn then close enough to interact with. 10 out of 10 times.
Video proof : https://youtu.be/TK-Z0ukFDrc
Edit : After further testing. It seems like the chest is actually in “The Great Sea” zone which makes it despawn for the player. Swimming just a few feet towards the coast changes the zone to Silverpine Forest and spawns the chest back.