1) Was playing on experimental server UK-9
2) In French language when I realized it is not fully done yet
3) Changed to English in the games Options
4) I did not hit 'Restart' but 'OK'
5) I quit the game manually and close the client
6) When restarting and joining back UK-09 backpack disapparead completely
7) Shoes disappeared too
8) They are not hidden but really losty because I have been able to find and equip new stuff after