An Engage Meeting is not displaying the icon to indicate who received an email invite in iRep.
The picture below shows which Attendee is invited through email and which one is not invited through email.
Engage Meeting Invites are built on top of Approved Email. The end-user needs to have Field Level Security (FLS) to the Related Transaction ID on the Sent Email Object.
CRM Help Documentation: Sending Engage Meeting Invitations via Approved Email