I’ve noticed that the first time I login to my account each day, all of my characters have their backpacks hidden. When I say hidden, I mean the checkbox in your equipment panel is unchecked. I know for a fact that the box was checked when logging out.
This seems to only the FIRST time I login every day. At character select, I can see that none of my characters have their backpacks shown. I can login as a character, show their backpack is then shown in the login screen. Like I said, this seems to reset every day.