The inbox was treating mail the site had sent as if it were a new unread reply: the conversation header showed the wrong people, a welcome email sat unread, and member sends were not filed at send time so a Gmail copy arrived later looking inbound. A second email on the same subject a few minutes later was also folded into the first message, hiding the follow-up. Sent mail now looks like sent mail. The header follows the latest message, a member send is recorded when it goes out, older copies are corrected when the inbox is opened, and a follow-up with different wording stays visible as its own message.