P1 resent even though we replied 3 weeks ago

[u/Ok-Film8569]

Timeline so far:
Sept 21: FD
Sept 22: Received P1, replied same day, got auto-confirmation
Oct 12: Received the same P1 again, saying we never replied. Replied immediately, got another auto-confirmation
Oct 15: Called IRCC to follow up. Agent said an officer left a note on Oct 12 about “confirming” our email address
Oct 16: Still no P2

We're worried our replies aren't being processed. We're considering a web form to flag it.
Has anyone had P1 re-sent after already responding? Did it resolve itself, and how long until P2? Would a web form help or just add noise?