Yes, speaking from experience submitting it again will be equivalent to waiting another 2/3 months for an update.i think they may start counting another 2-3 months again... because they said the processing time starts from the date that they receive your complete application. but this is weird, the online portal wont allow you to submit if you did not sign the declaration. did you try to contact them?
I applied for a card renewal back in January, got the application "returned" (Reason: "Incomplete application") in March and the only thing that was highlighted on the form was the consent and declaration section (which is odd since it is mandatory and you can't submit the application without it).
Fast forward to today, my application got rejected again for the same reason.
Just got off the phone with IRCC, but they weren't very helpful and essentially just advised me to put in a paper application lol