Listed on the ATC website "Problem Bear Activity - Mt. Rogers/Thomas Knob Shelter (05/10/2018) Problem bear activity has been reported at Thomas Knob Shelter in the Mount Rogers National Recreation Area in southwest Virginia, mile 498.5 from Springer Mountain, Georgia."

In reddit found this "I did an overnight up there last night. Was camping north of the shelter near the water source at the crest trail. A guy from the ATC was going around the sites warning people about the problem bear so I made sure I had an extra good hang.

About 1 in the morning I woke up to bear horns and people yelling "no bear, get on bear" a few campsites away. That seemed to scare it off but I did hear the horn again about an hour later. Needless to say I didn't sleep very much.