I moved a thread to a different section this morning using Change All.  this afternoon I found a later reply still in the old section, and it showed the original message of the thread as being in the original section.  Checking I found the original message and it's replies had indeed moved to the new section. (??)  So I used Merge Source on the new message and Merge Destination on the original message once I got to it while reading messages--and it worked fine, all messages in the thread are now in the new section.  But--that last message should have posted to the new section to start with, I think.  My only thought is that it was being posted around the time I moved the thread but in checking, I moved the thread around noon and that last message wasn't posted until around 12:30.  For what it's worth. 

First message in thread #797074