This started a few days ago. I've been getting texts from friends with iPhones in the wrong order, and seemingly they are getting mine late. So I texted a friend whose grandmother was in the hospital yesterday, and her conversation with me looked like this. These texts from her arrived around a minute apart each. I think the intended order of them is fairly obvious. It's worth noting that every time I send her a text, the read receipt line under the text shows a little clock for a few seconds or more, which I think means it hasn't been recieved by her phone yet. Also worth noting that I had a conversation using the same stock messaging app with my mom yesterday who has an android and I don't think we had any such issue, but that may have actually been RCS.
Anyway, here's the example. It's not the only example I've had with her or with another iPhone-using friend in the past couple days.
Me: Hey, how's your day? Any updates about your grandma?
Her (a few hours later): I feel relieved
Me: does that mean you got good news?
Her: how was your day?
Her: yeah
Me: my day was good, (proceeds to describe what I did that day)
Her: my family feels relieved too
Me: what was the good news? Your grandma is okay?
Her: Hey $bionicjoey, I didn't get much sleep last night but I just heard that the doctors say my grandma is out of danger.
Edit: I texted her last night saying something weird was going on after that exchange, and then this morning at about 7:30 AM I texted her saying "let me know as soon as you get this". She just texted me at 2:30pm saying "I just am just now seeing your texts"
So I may have done this a bit out of order, but I did actually try turning it off and on again yesterday, and tested afterward and the problem persisted. Not sure what you mean by a reply versus a fresh message though. And just now I checked the smsc and it matches what people say online it should be for my carrier (found an old Reddit thread).
It’s important you do it in the right order.
A fresh message is where you tap the New Conversation action button, enter the contacts name or number and then type the message (rather than open an existing chat)
So: Off, wait, on, wait, fresh message.