eM 10.4.506 threading quirk

I have a message thread here in eMC that shows the reply from the recipient then it shows a follow-up email from me twice. Then the 2nd reply from the recipient.

The duplicate follow-up email from me shows as being in my Inbox as well as my Sent folder. Both of these emails show the quoted message from the recipient that I am posting a follow-up question from.

Why is eMClient showing what amounts to be an outbound email of mine in my Inbox??