Symptoms
If an exception is created for a recurring meeting series, external attendees are presented the “Send the Response Now” option even though the meeting invitation was sent without a request for a response in Microsoft Exchange Server.
Resolution
To fix this issue, install the following updates, as appropriate:
Cumulative Update 12 for Exchange Server 2019 or a later cumulative update for Exchange Server 2019
Cumulative Update 23 for Exchange Server 2016 or a later cumulative update for Exchange Server 2016
