Continuity mistake: The bell in the Salvation Army bell ringer's hand switches between up and down as the shots change while Dina gives him bell-ringing advice.
Continuity mistake: Jonah's hand repeatedly alternates from being on the shelf to the top of a storage bin several times as he speaks with Kelly in the storeroom.
Chosen answer: He's just gained weight. It looks like he slowly started gaining more weight around 2006 or so. In "Kids in the Hall: Death Comes to Town" (2010) he's noticeably heavier than his younger days (he was on SNL 21 years ago). By the time he was in "Man Seeking Woman" he looks very similar to how he looks in "Superstore."
Bishop73