Every so often, we hear reports of emails that are showing up in reports as opened, but haven't yet been received by the recipient. So why does this happen?
Emails being marked as opened that haven't been delivered to the inbox is usually a result of antivirus / security software scanning the email message. Our system reports opens based on link clicks and image download. When an antivirus / security software scans an email prior to delivery, it can sometimes register an open by 'downloading' the images, or 'clicking' the links.
To narrow down whether an open status might be due to antivirus / security software, you can send a test email to yourself, through your personal (non-work) email address. If the email doesn't register as an open until you physically receive and open it, then it is likely that some software on your office network is registering a false open.
In this instance, you might like to follow up with your IT team to see if there is anything they can do to prevent this.