accidentally making new group chats

I do not know how to explain my situation very well, but I will try, lol.

I am in a group chat with three of my friends (who all have iPhones). Often times, when my messages send as SMS, my friends say that I made a new group chat. However, I do not see a new group chat on my end. On my screen, it is still the same “old” group chat.

Just now, I tried to start a group FaceTime call on that group chat, and one of my friends said that I made another new group chat. But I did not see a new group chat. I do not make these group chats on purpose. It just happens. I do not know how it happens.

I did some google searches concerning my situation but my searches are to no avail. I have an iPhone 15 that uses both my email and phone number. I use Verizon.