IMAP performance "should" be a clear issue with clear paths to resolution. This one is a bit strange. There is no way to resolve it other than to test adjustments and configuration changes to the IMAP server in production, this exact issue cannot be replicated in staging when it's cause is not so apparent. However, we will continue to test changes until we get it right. While we expect it to already be better, it may take some time to be confident in that, so this status will remain open for an extended period of time regardless of the state of the issue.