Double chest across chunk becomes separate and appears empty after traveling through nether portal.

all of a sudden, as i was flying with my elytra back to my house, i went to open a chest. and the chest appeared to be a double chest, but not  adouble chest. just two chests beside each other. and when i looked inside the contents of the chest. everything was gone that was in the chests! i dont really know how it happened it just happened randomly. i cant put anything in the chests either.