I'll dump the stuff if nothing helps or softens the petrified chunk...but...
I've tried my own remedies that have worked previously with regular light/dark brown sugar.
It's a totally hard softball sized glob.
Microwaving does nothing. Laying sheet of damp paper towel on top of glob then securing in air tight Tupperware didn't work. Apple slices in air tight container for a day + didn't work. In Tupperware for 2 days after putting few drops of water on top of glob didn't work.
Storing it from the get go in plastic sealed bag created this.
Suggestions appreciated. thanks.