Hi Glenz_05279,
I believe Tordawgs is referring to things like, reloading their save, clearing the cache of the console (shutting it down and unplugging for 2 minutes before rebooting), reinstalling the game etc. (Tordawgs please correct me if I’m wrong or let me know if I missed anything)
I often suggest clearing the cache of the console to players as a first step in certain issues. Unfortunately there is no known workaround for this issue at the moment. Should any workaround be discovered, it’ll be posted here: [Known Issue][PS4/XB1] Inventory and Tool Belt Reset (Multiplayer)
If all of the items were in your inventory, please let me know what was in your tool belt when this happened and if you are playing on XBox as well. If you like, you can create your own bug report and I will respond to you there. If your crates were not in your inventory, then this is likely a separate issue and a separate bug report for this would be appreciated.