It does indeed happen. Happened this past Monday, May 2nd and will continue to happen for the next several weeks.
Monorail81--Indy has taken over CT 1 so Mariner has been bumped to CT 5. Only on days where Indy will not be using CT 1 will Mariner get to move back over there. Schedule is only released through June, so we'll see.
Source: https://www.portcanaveral.com/getattachment/Cruise/Cruise-Lines-Schedules/CPA-Website-Schedule-Apr-Jun.pdf.aspx?lang=en-US