It that US investors, funds etc etc are in desperate need of cash back home & are selling up their overseas assets to try to fill plug the holes at home. The result being that when they sell their O/S assets they have a pot of O/S currency that they need to convert to USD to repatriate it = higher demand (short term) for USD.
I'm betting it's an aberration & that once the O/S asset cupboard has been emptied the USD will resume it slide into M3 induced oblivion