No explanation is given for Catherine stepping down as swing shift supervisor. I assume that she felt it was conflicting with her parenting—“Weeping Willows” sort of hinted at it, though that episode implied that it was also her attempt to have a social life that interfered with her time with Lindsay. An explanation would be nice since Catherine returning to Grissom's team is a demotion of sorts, but hopefully we'll have one in the next few episodes.
Grissom's request in the finale was a problem for Catherine, or could have been—he asked for his guys back, but did that include Catherine, or was he just talking about Warrick and Nick? And what if he has gotten them back, leaving Catherine with a new staff (and perhaps a lot of resentment). It's a conflict it seems the writers have chosen not to play up, for better or worse.
