Abilities won't work?

I just had a match with a Lux who couldn't use her W the entire game. Even though she had full mana and obviously it was off cooldown. She logged out and back in. but nothing worked. The thing is, I had a match a couple weeks ago playing Caitlyn where all of my abilites stopped working about halfway through. I could auto attack just fine, items and other commands worked just fine too. Just QWER were useless. I didn't have that issue again and it's been weeks, I just thought i was my computer maybe. Keep in mind I was having no connection issues that I could tell, and apparently neither was today's Lux. So...what's up with that???