Group Text

Probably they are from Android users.  All responses in a group SMS are sent as individual text messages and the recipients can’t see the other responses from the group.

Learn how to foward SMS/MMS text messages across your devices, like from an iPad to a Mac.

Add or remove someone from a group conversation

Anyone in a group iMessage can add or remove someone from the conversation. You can remove a person from a group iMessage that has at least three other people. You can’t add or remove people from group MMS messages or group SMS messages.

Types of group messages

The three types of group messages that you might see are: group iMessage, group MMS, and group SMS. The Messages app automatically chooses the type of group message to send based on you and your recipients' settings, network connection, and carrier plan. For example:

• If you and your recipients are using Apple devices and iMessage is turned on, then the group message is sent as an iMessage.
• If you send a group message to people who aren't using iMessage, then the message is sent as an MMS or SMS message.

Do more with Messages

• Learn how to leave a group message, or add or remove someone from a group.
• Name your group messages to make them easier to find.
• Use inline replies and mentions to call attention to specific messages and people in your group messages.
• Explore the latest features in Messages to stay connected to the conversations that matter the most.

Same thing happening to me today. This is a group of mixed IOS and Android users. We have been sending texts in this group for years and everyone can see all of the messages. I needed to remove one person from the group, so I started a new message ( a new group) since I can't edit the mixed OS group. Now members are sending me messages that they can only see the conversation between me and them, nothing from the others. They assume that I mistakenly sent the group message just to them.

The only difference from the previous group, besides one less member, is that I included myself in the group. I'm going to test to see if that makes a difference.

Ok - I noticed one more thing. Included in the new group is someone with what looks like an older Android phone. Based on some online research, it looks like that older phone could be forcing the group message into SMS mode with everyone seeing the message as if it were sent to them individually - same for replies. I’ll try a group message without that person to see if that’s the problem.