Could you please open the MSG file in Outlook and send its screenshot to us? We just want to make sure reporting the accurate difference between the original MSG file and the converted MHTML. Your cooperation is highly appreciated in this regard.
1. The sent date of the message is converted correctly. Outlook shows the sent time in your local timezone which when converted to MHTML shows it in UTC format.
2. The appointment time changes indeed and I was able to observe the issue at my end as well. It has been logged as NETWORKNET-34547 in our issue tracking system for further investigation by our development team. We’ll update you here once there is some feedback available in this regard.