No longer getting a Read receipt

[TextMeMaybe]

S9 plus user on Sprint. I don't text a lot of people and of the few people I do text, my brother is the only one with an Android phone, Galaxy s7. I use the Samsung messenger app and when I first got my phone all my sent text were green, no read receipts. Then one day back in September some texts I sent to my brother were blue and showed when the message was read. A day later they were back to green. Then the Pie update comes out and all my new messages to my brother are blue and I get a Read receipt. Until today. Now there back to green. I have changed any settings. Is this something my brother could have changed on his phone? Is this a Sprint issue?

 

[Rukbat]

That's part of RCS, and the industry is still feeling its way around TCS, so don't be surprised when things pop up or when they stop.