The other night I put a bedrock unbreakable armor set, sharp6 sword, stack of gapps, 127 str2 pots, 38speed 2 pots, p6 bow, and an ancient sword in my echest. The next day I logged in and it was gone! Please remove the ability for people to look at each others enderchest. This is more than likely how they are stealing from echest using the same method as /invsee.