iphone missing group messages found in search

I've been in a group message chat with three other people, one Android, for over a year. I'm trying to find a message that was sent about a week ago. I scroll back in messages and I see all dated yesterday, then there's a jump of about a month to the last one previous to yesterday. I can search and find the message, but when I touch it to navigate to it, I'm brought to the group message session that I was previously scrolling in and it is still missing about of month's worth of messages--including the one that's found in search. In summary, how can I see a message in search that can't be navigated to? It seems like it might be a corrupt index or something, but why would it appear in search?