I suspect it will be due to the heating in the house. The air will have got a little too dry for it, mist or stand pot on a tray of damp pebbles/gravel. or conversely it may be just getting too cold, if left behid the curtains on a night.

Yes I agree you can do a bit of artistic pruning to get rid of the dried bits, but keep away from the radiator or direct sunlight. I had one that bounded away when I gave it a dring of diluted Epsom Salts.