This is what I am cautiously hoping for - that it comes back to them and they resend to the corrected address. I called IRCC yesterday (40 min on hold!) and at least they corrected the address on the profile. They said that for now they are not able to do anything - they only take action after 6 weeks since mailing (according to their rules). I plan to wait a coulpe of weeks and then call again to see if the card turned up back on their end. The problem is I am not sure how efficient their process is in terms of dealing with returned mail - maybe it is another huge backlog on their end (waiting to be processed).incomplete address usually will result in send back to cic office, you have to call them and ask them if the card is with them, then they will send again to your correct address.
Wondering if it would make sense to also put a web inquiry - so that there is some written record of what happened and so that do not close it as 'complete'. Interestingly my mom's case no longer shows up online (she got her new card back in October) so it seems they do close status access at some point of completion....