The game is suffering a few bugs with saving inventory among others, the developer made a list of fixes for the upcoming patch.

"Crashes:
1 - 'Code 4' when selecting 'Xbox Live' caused by invalid index. Fixed.
2 - Reports of Random 'Code 4' while exploring. Added exception handing to begin tracking this.

Inventory Loss:
1 - Tents and Inventory not saving in 'Local Survivor' caused by uninitialized character parameter, could happen in rare case while in online mode. Fixed.
2 - Tents and Inventory not saving in 'Xbox Live' session caused by 'Main Menu' being active on transition out and player pressing 'A', causing random selection of other menu options. Fixed.
3 - Tents and Inventory not saving in 'Xbox Live' after joining and online session. Caused by current mode never being initialized, defaulting to whatever previous state was. Fixed.
4 - 'Players' Menu not being available in 'Xbox Live' session, caused by 'Local Survivor' being the state when actually online. Fixed.

Loss Control Input:
1 - Loss of input when Vehicle menu open and another player attaches to the vehicle. Caused by code path to close vehicle menu never again being executed. Fixed.
2 - Loss controller input when attaching to a vehicle. Caused by player and vehicle properties not being fully initialized when player joins session. Fixed.
Note: other conditions may cause this to happen as reported in forums.

Vehicles:
1 - When joining a session some vehicles that had been moved would not spawn correctly for client. Caused by position of vehicle not being transmitted on spawn. Fixed.
2 - Vehicles are no longer bullet proof, you now take 50% the damage of each projectile.

Melee Issues:
1 - Walking backwards and not being able to hit zombies. Fixed, Player melee distance increased when walking backwards.
2 - Zombies having slightly larger hit radius than players. Fixed, zombies and players have same hit radius.

Host Migrating:
1 - Getting a zombie beat down when host migrates. Fixed, Simulation pauses until host migration complete.

Inventory Menu:
1 - 'B' button used to drop items, very unintuitive. Fixed. 'B' and 'Back' button will close inventory menu, 'A' button used to drop or pickup items, depending on what menu pane you are in.

Invert Y:
1 - Will now apply to camera control while driving vehicles.

HUD:
1 - 'Back' and 'Start' button UI switch, Fixed.

Sound:
1 - Zombie Crowd, Run and Attack being to loud and stereo left/right not working. Recompiled sounds down to mono (I have issues with MS XACT3 3D sounds working on the Xbox) and turned down volume.
2 - Foot step sounds while driving a vehicle, Fixed."