Yup.

Here's a couple of examples, the first one on NK:

I was looking for a one way LAS-DFW, and for weeks it was $59. Finally decided to pull the trigger, and it went up to $89 that very morning IIRC - I could look as I purchased at that point

Checked again later that afternoon after the morning purchase, and it was well north of $100.

Second expample using UA:

Hub attack on DFW, $434 r/t to HKG, one I did not see until the next day, but much to my amazement it was still there.

Just for grins and giggles (yes, I know that's not how that one goes) I looked the next morning, and lowest fare was $1,341.

OK, one more, since still have my DFW fare alerts set from when I used to work there:

DL had similar price during its own hub attack, but that was gone before I ever had a chance to click on the link even before my morning coffee - but this was a a few weeks ago and purely an exercise as I have no intention of flying to HKG on DL. Flying from YVR on NH in Biz