I'm super confused, are the using a... well, I don't know the terms, but a fancy "a" for the straight face and a simple "a" that's the circle-bar O|-shaped "a" for italics?
Is that common in fonts and I never noticed before?
Yes, many fonts use double story 'a' for roman and single story 'ɑ' for italic. Calibri, Segoe UI, Times New Roman, Droid Serif, Merriweather, Consolas, and Source Sans Pro are examples I found from quick searching.
Many fonts having "real italics" would use a different shape, whereas those with only "slanted fonts" would not (like Verdana). It's only a rough rule, but you can assume that most serif fonts will use "real italics".
