Hello Jane,
Thanks for your sharing of the picture, I checked this on my side and I do not have the same problem as yours after inserting the Zoom meeting link and send out the updates. Please see:

Given this situation, please try to send the updated meeting invitation email to your personal account and then sign into your personal account to check the whether it is a Zoom meeting.
In the meantime, I will send you a test account via Private Message (PM), please sign into the test account and check if there is the same result after remove teams meeting information and insert the Zoom meeting link.
By the way, for the existing meeting, if it still show as Teams meeting for external attendees, then to workaround it, you may send an email to these external attendees and tell them that they can also join teams meeting without a Teams account and share the following document with them: Join a meeting without a Teams account.
Best regards,
Jennifer