Not the best analogy, but can you cook a steak so that it's both 'under cooked' and 'over cooked?" Sure! Set your grill at 1000*F (if you could do such a thing) and burn the hell out of the outside, but leave the middle cold and raw.
It's helpful to do a quick inventory of the factors that each term (under and over) corresponds with:Overextracted
Grind too fine
Brew time too long
Turbulence too high
Temperature too high
Brew-ratio off (too much water to too-little coffee)Underextracted
Ground too coarse
Brew time too short
Uneven contact (i.e., a "dry patch" in the grounds that didn't brew)
Temperature too low
Brew-ratio off (too much coffee to too-little water)
Coffee too fresh
Coffee density too high (for those brewing parameters)
So simply put, can you have elements of the first list and the second list in the same brew?