Who I have the same questioned this topic

Been in an important group chat with 2 other people, one is on Sprint and has a droid, the other is on AT&T and uses an iPhone. I am continually receiving delayed texts from the AT&T person several hours later. But, I get the texts from the Sprint person immediately. And, the Sprint person is getting the AT&T texts immediately. The delay is only happening on the group text, and I have missed some important information because of it. This has been happening for 3 weeks when the group chat started. I use the Verizon Messages+ app and I have a Samsung Note 8.