The worse part : If you happened to modify the contents of your inventory during the lag , like upgrading , selling items , you lost those items.
I upgraded my talisman during the lag and it did not go into my inventory, it's gone.
Let's hope that they can fix this issue, and return the items to us somehow.
EDIT : The lost items are now in my inventory , as they were before the lag happened. Nice. They probably reverted to a previous backup of the database, created before the lag happened