group message with android and iPhone users

We have a group text that includes Android and iPhone users. All users are on current ios 11.2

We have some Android and some iPhone users that can not see all of the group messages. However, we have a few iPhone users in the group text that can see the entire thread of both Android and iPhone users when they contribute to the text.

We have confirmed settings and no other users are blocked.

We have deleted contacts and set them back up

We have deleted the group and started another one -- but it seems to be the same group of 5 out of a 17 group text.

Any other insights we have not tried.