Hi Katie -
You may want to check your Event Emails to see what you have Active and Enabled. There may be a "thank you for submitting your registration email" enabled as well as a "Registration Pending" email. Based on this screenshot, it shows that two emails were sent, but it doesn't necessarily mean that it was the same email message.
You can also try running a "Sent Email Details" report to confirm exactly which emails were sent out:

Hope this helps!
------------------------------
Rebecca Yousif
Senior Administrator - Event Technology
------------------------------
Original Message:
Sent: 10-30-2023 14:29
From: Katie Collins
Subject: Approval Pending Notification email was sent twice
A registrant received an Approval Pending Notification email at 11:37am and another of the same at 11:42am. At first I thought that maybe he was sent a plain text email and an HTML email, but the settings for the email are to only send the HTML version. Any ideas on why he was sent the same email twice?
Thank you for any help!
------------------------------
Katie
Midwest Renewable Energy Association
------------------------------