The recipient does not have an iPhone. Some other platforms break down text messages because of the limited number of characters per text. So they will receive 4 separate texts. Was it a long text message? I saw this issue a few days ago when someone asked about it. In any event, it's not your phone.
This is an iPhone used by my wife. The message is only on one recipient, my son and he also has a iPhone. The message is still there. One other question, (obviously we are not experienced iPhone users), some of her text have a green background, others have a blue background. Someone told me the blue messages are going to other iPhones and the green messages are going to other types of phones. Is that true? Thanks for your help
bear962 as an FYI, using iMessages actually takes more data to transmit than the same message as an SMS (texting plan). There is an overhead associated with every iMessage. Delivery confirmation, user is typing status, possibly when it was read. And even more data is used if you send a Photo or Video. iMessage sends at full resolution where SMS sends in reduced. For some people it is cheaper to use only SMS and avoid the data usage. People with 1GB only plans and unlimited SMS should always use SMS to protect their data usage.
I was explaining, not directing! As a dinosaur with unlimited data and texting, I know my experience can not be applied to most current accounts. But you expanding on my comment can help OP choose the best use for him and his family.