You say no sign of an overnight hypo and you have good hypo awareness..
I think your sign was of a probable overnight hypo is feeling rotten this morning...
As it sounds you slept through it, and your liver dumped to bring you out of it.. Which would go towards explaining your hypo after a correction... Because your liver dumped, it takes time to restock your liver glucose store, and your liver will replenish this before it starts dribbling out any background glucose into your system, the knock effect is that the background insulin effectively becomes quick acting and combined with your correction dose, stripping the BG down a lot quicker..
If you totally convinced that you haven't slept through a night hypo..
Take a look at what you did yesterday, did you eat anything that had a long delayed impact on your BG? Perhaps different exercise, increased stress that might have raise your bg?
But as nigel said, it may be wise to set your alarm clock to check your bg around 2-3am in the morning, see what's happening here