recovering ability to text multiple recipients

Today I discovered that I was suddenly unable to text the other three members of my family. Whenever I tried to type all three names into the To: field, the Messages app would exit as soon as I entered the third family member's name. I tried all permutations of the ordering, nothing worked. I ALSO found that I COULD send texts to four people, including my three family members. Very weird (the behavior, not my family members 😁). After lots of trial and error, I deleted the conversation thread consisting of these three family members and ... voila!! ... I can text my three family members again.

Anyone have any insight on what my have been going wrong? Just curious.