"Adaptating" is the sort of word you get when you have been awake too long. In my case the specific time involved was probably around 20 hours when I made the slide that contained the offending word. Spellcheck occurred, or rather did not occur at around Waking+28 hours. I finally made the discovery at Waking+30 hours, in the middle of my presentation. That's not a fun time to discover such an error. The misspelled word was highlighted in blue just to make it more prominent. Also, it repeated since I had copied that slide for use towards the end of the presentation.
Next time I'm working harder to get things done ahead of time so I can actually sleep before my presentation. Thank goodness for my experience with midnight shift transitions. I'm pretty sure that's a large part of how I managed to actually stay coherent enough to give a presentation after 30 hours without sleep.