How did I rcv this unrelated text

[AC Question]

I have the Samsung Galaxy S4. Recently I was texting with my daughter about dinner plans. I rcvd an unrelated text from her and when I responded, she wanted to know what I was talking about. I went back thru our texts and that particular text was not in the thread. Since I knew I saw this text, I went back thru every thread on my phone and its nowhere to be found. I have had this happen about 3 times now so I know I'm not going off the deep end. Any ideas?