Dungeon destination set with hashtag not retained

If I set a dungeon destination with a hashtag (e.g., #serpent), the destination is initially set and the event stream's map label displays "Going to Serpent Trench". After subsequent tweets (that do not set a new destination), the #serpent destination is forgotten and my char ("bifyu") resumes random(?) wandering. No destination label is displayed under the event stream map.