Host must register for meeting, but then is not allowed to register because they are host.

We recently had an issue with a host joining a Zoom meeting. Our administrator scheduled a meeting and assigned a host. This meeting required registration. When the host attempted to join the meeting the registration form opened up.  After completing the registration form, the individual was informed that they could not join because they were the host. They attempted to sign out of Zoom and rejoin but had no success. Fortunately, another individual with host privileges was able to join and sent an invite link directly from within the meeting, which allowed the host to access the meeting. Any thoughts on why this occurred and what can be done to prevent this? I appreciate your help!