That's one weird bug :/
I tried doing what you did, same location, same activities, I even installed interface mode you got and 20+ minutes walking there, mining on overweight and nothing. Sometimes deleting client's cache helps in weird moments... I would suggest downloading fresh client, run updater (just in case there is something new) and try again with clean client, without any interface mods. If that doesn't help try doing same thing on another character.
Let us know if any of that helped.