Mail not showing my sent messages in thread view

Hello Abby Cooper,

We would like to see how we can help you with your Mac Mail Views. Update your settings with the steps in this link and get back to us if you have any questions: Change Viewing settings in Mail on Mac - Apple Support

Cheers!

Then have a few suggestions ;

1 - Get Support Choose a product and we’ll find you the best solution.Start now and open an Apple Support Ticket as they are Apple Employees to deal will these types of issues . 

2 - Product Feedback - Apple and make it known to Apple regarding this ongoing issue 

FYI - Yesterday Mon Jan 23, 2023 - Apple released another update to Monterey bringing to version 12.6.3

If not already installed

Well, right now I do not have enough " Threaded Conversations " to illustrate whatI am seeing on this computer.

Without revealing any Personal Information, like Full E-mail addresses.

Perhaps if the User ( you ) could provide a Screen Shot of what you are seeing, we maybe better able to understand the situation

Screen Shot via 3 keyboard combo Shift Command 5

Post back the screen shot via image below

Thank you for the above illustration.

" Shot in the dark "

I communicate with my two sisters on a single e-mail originating from one of use.

If I Change the >> Subject Line << on the reply e-mail, the " Threaded " / "Conversation " in sent is broken and does not appear

In Apple Mail >> Top Menu Bar >> View

Enable " Organize by Conversation "

image below

ALL email sent from 1 E-mail Account or from more than 1 E-mail account ?