There are two possible causes.
The first possibility is that the system filters out the pending emails before building the mailing list based on the filter setting configured in the email template. With more filter settings configured, the amount of the pending emails will likely decrease.
The system will scan the pending emails again one day before the scheduled sending date. If the pending email doesn’t fit the filter setting from the email campaign, it will not be sent on the scheduled date.
For example, say you plan to send out review requests and have chosen to exclude the buyers with negative Feedback in the previous order in the filter setting. The day before the system is scheduled to send out the review request emails, the system will scan the order criteria again. If the system detects the Buyer has left a negative feedback in the previous order, the system cancels the queued email. Your email will not be sent out by Feedback Central.
The second possibility is that the amount of the emails that are scheduled to be sent out today won’t be presented in the data of the pending email. The index here shows the number of emails from the last 6 days.