Well, not entirely blasphemous, but a bit peculiar. 
This happened to my model ages ago, and I didn’t know what happened to it. I finally discovered it again, on accident, but I figured out what happened. And because the lecture includes a subdivision already is entirely a coincidence!
If you attempt to use a hotkey to change between Vertex, Edge, and Face selection, you will notice there is none. Instead you only get a selection window after pressing Ctrl+Tab, of which you have to painstakingly hit the button 1, 2, or 3 AFTER hitting the already complex hotkey, making it a very unconventional way to switch.
Well because of this, if you hit Ctrl+Tab+1,2, or 3 in one sweep, instead of getting the desired effect, it turns out it is a wierd 3-button hotkey to apply a subdivision surface modifier AND choose how many subdivisions it has. You can go from 1 to 5 subdivisions, but if you dont hit the keys fast enough, it will instead change your object mode or change your selection type.
Wow ok, its not as funky as i thought. The hotkey is actually Ctrl+1-5.
^Automated subdivision at 5 subdivisions
Ctrl+1 !
^Subdivision hotkey changing Subsurf to 1 addional subdivision
I will be making a macro for this tommorow so that I can change between verticie, edge, and face with ONE button like a sane person.
