Behavior After Sending an Email Not Consistent

[admin at nosuck.org]

Hello.  I am scratching my head.  Please help.

After replying to an email, Mutt does one of three things:

⋅ It returns to the pager, showing the email to which the reply was made.
⋅ It returns to the index, selecting the email to which the reply was made.
⋅ It returns to the index, selecting the second-oldest unread email.  This  
happens frequently and is the most annoying of the three.

Please note that I am able to reproduce the inconsistency even after running  
“unhook *”.  However, while I am ABLE to reproduce the inconsistency with  
the following configuration...

> set sort = "threads"
> set sort_aux = "last-date-received"

... I am UNABLE to reproduce the inconsistency after changing “sort” to  
“reverse-threads”.

Is there a way to debug this?

Mutt 2.2.9 (2022-11-12)
Linux 6.3.8-200.fc38.x86_64 #1 SMP PREEMPT_DYNAMIC Thu Jun 15 02:15:40 UTC  
2023 x86_64 GNU/Linux

Thank you.