Separated Messaging/Text Histories

Why when I click in some text/messaging conversations they show only one participant's texts and not both from the conversation  For example, it is obvious that one participant is asking questions and subsequently responding to answers from another recipient, however, it does not show the other participant's responses.  I have to then click on separate text/messaging conversations to find the other half of the conversation to ultimately piece it together into a complete conversation.  This does not happen in all conversations, just some.  Is there a setting or some other way to view the entire conversation in one conversation/thread?  Why does this incomplete conversation only occur in some conversations?

Thanks!