From where I sit this is likely one of two things:
1 - Canada cannot appear to have chosen the candidate fighter before a 'competition' is declared, therefore must cast the net wide. It may still have eyes on the SHornet, but needs an apparent competition. Boeing will eventually get a call for those 'buy now, pay later' "Best Buy" rates it promised the Canadian Govt to keep it in the fighter business.
2 - The Trudeau Govt is slowly waking up to the fact that SHornet will become obsolete far sooner than it wants for a 'new type'. Thus, it must now re-position to select F-35A (or C) once more, without unconvincingly destroying their election promise.
Out of the options above I would side with option 2 because I know that Canadian Air Force SMEs have recommended F-35 each and every time they have been asked to provide the military judgement on the matter. Sadly it seems to have fallen on deaf ears, much to the frustration of the Air Force experts.