Hi, you might have to call IRCC or make a query through an online web form and get confirmation about your parents situation of staying past 6 months. Or we need to hear from someone who is/was in the same situation but it might be difficult to locate them in time.
I’m hoping with so many on and off travel restrictions along with the fact that it was an initial Super Visa entry, you might be okay but it’s not upto me to decide. Travel restrictions are a recent thing of the last one year or so. A stamp with a date would’ve been so much convenient for your case and you are in a weird situation where your parents didn’t get a stamp and they’ve stayed way over 6 months so I’m not sure what’ll happen now. Of course they will not order them to leave the country immediately since they have a valid super visa and once you properly explain your situation then they will surely help you with the best solution.
Either way, once you clarify with someone at IRCC, apply for their visitor record extension. Everything takes too long these days so best to apply as soon as you’re ready and eligible.
And just to give you an update about my parents -
PGP 2020 PR - still waiting for AOR.
Visa Extension - still awaiting updates, no medical or any other requests yet.
Good luck! Let us know how it goes.