Q: Why did I receive a reply when there was no 'open' event?
A: For Yesware tracking to properly record an 'open' event, the recipient would need to open the message and load the unique tracking pixel. If the recipient's email settings are to not display images, the message can be opened and read without loading the tracking pixel. We are able to track the reply that is received, as that data originates from your inbox once the message is sent to you.
Unfortunately, there is no good solution to this issue, as it is based on the email preferences of the recipient. We find that it is rare that recipients have chosen not to display messages but it does happen (usually with Outlook users).
Additionally, if this recipient is on an Apple device they may be opting to not share their information. See this article for more information on this update.