I think it's a mistake. Rather than sharrows, I think it should be a single arrow pointing in the direction of travel. Looking on Google Streetview, there are a few spots just north of Lincoln (Kedzie/Hood) where single arrows are used, then the next marking is a sharrow.
Based on what I'm seeing on Streetview, it looks like it's been this way since at least 2007.
'Definitely looks like it was mis-marked.
Maybe they picked the wrong stencil? Or applied it before the bike lane was drawn?
I think the sharrow predated the lane but am not sure. I ride that stretch a lot but do not really pay attention to the markings. Kedzie from Lincoln to Howard is very bike friendly.