Messages Green in Preview but when I click chat, they are blue. Only with one person

When I search up a word in the search messages, all the texts that I sent come up as blue except with one person. All of my texts that I sent (in the preview) show up as green. But once I click on the message and it opens up our chat, my messages are blue. And when I sent the messages, they were all blue. And the other person and I both had wifi and date and iPhones.

Why is this?