the person I know forgot to apply for new card while old one expired, official let her in(she flew to buffalo, took a uber to the bridge, walked through the bridge and someone picked her up on the canadian side.)
are you flying with the prior card expired? if so, my guess is no, but I do know people who flew to Buffalo and walked back through rainbow bridge in Niagara.
where do you see the rejection? did they email you? I saw comments from prior month log that people re-upload photos after rejection due to this reason.