On the Xbox One Bedrock edition we encountered this issue a few times. For us it seems to be related to connectivity. If the xbox is offline or having connection issues the people connecting are treated like guests. The lose all their stuff when they save and exit. Only player 1 retains all this things on rejoining. When we made sure we were online and had a good connection the game behaved properly with players joining and loading properly. I don't know if this is an exception or already known.
Jaxem
On the Xbox One Bedrock edition we encountered this issue a few times. For us it seems to be related to connectivity. If the xbox is offline or having connection issues the people connecting are treated like guests. The lose all their stuff when they save and exit. Only player 1 retains all this things on rejoining. When we made sure we were online and had a good connection the game behaved properly with players joining and loading properly. I don't know if this is an exception or already known.