Messages hidden after conversation close/reopen
So, I accidentally clicked the close "x" on a 5-person ongoing conversation in Messages on my Macbook Pro. Immediately choose Edit > Undo Close Conversation. After a few moments the conversation came back, but only with a single message that someone sent just about when I closed the conversation. Checked my phone: the full conversation was still there. OK fine, my accident deleted the conversation history on the Mac. So be it.
Then I get this what-the-heck idea to try a search. So study the conversation on my phone, pick a unique word, and search on that word in Messages on the Macbook. Up comes that part of the (not-so-deleted-after-all) conversation! (It brought up the bubble that actually contained that word, as well as the other bubbles from that day, which appears to be standard Messages behavior). So the older conversation content is still on the Macbook. But if I close the search and try to scroll back through the conversation history, it still only gives me the one recent message. I thought the older messages might have split off into their own conversation, but I looked and they did not. Tried quitting and re-opening Messages, no difference.
Questions:
Anyone seen this? Any ideas on if and how I can bring the older messages of this conversation back into the scrollable history?
(As Messages have in many ways replaced email, it would be nice to get a firm grasp on how message preservation and related behavior works. Working towards that goal...)
Mike
MacBook Pro with Retina display, macOS Sierra (10.12.1), 13" Late-2012