Now this is the weirdest thing. Just now I accessed the account as usual and — voilà! — everything showed up! Used the same browser, the same wallet, password, etc. The only thing that was different was that my VPN was turned off. Can that make a difference? Is my account connected to the IP address from which is was first established?
If so, you may want to advise users that VPNs don't work well with the light client.