The chat for a specific contact on WhatsApp disappeared even though the disappearing messages feature was not turned on

I recently switched to a new iPhone 15 Pro Max and successfully backed up all my data, and everything seemed fine. However, I've encountered an issue with certain contacts where the messages I send and receive disappear after I exit the WhatsApp app. The chat only shows previous conversations, and even though I can see a preview of the last message on the front page, clicking into the chat reveals only the conversations from before the transition.

I've verified with the contacts facing the issue, and they confirmed they have all the new messages. This problem seems to be unique to my side. This issue doesn't occur with other contacts, and the disappearing message feature is disabled. Despite restarting my iPhone and reinstalling the app, the problem persists. I've reached out to WhatsApp support, but they haven't provided a solution.

Sharing this to see if anyone else has encountered a similar issue.