Hey bud, how's it going?
Unfortunately this isn't something that you can turn off. This is going to be something from the senders device/MMS protocols. Sadly there is nothing you can do besides just delete that portion of the message.
Have a great day!
I had an S7 and never once had that happen. This is only happening on my S10+ and only with group messages. Each person in the group sent me an individual message and none of them had <Subject:NoSubject> on their message. If it was from the sender I should get it from at least one of them individually. <edit>
<Edit> Of course it doesn't say "<Subject:NoSubject>" when they individually text you because when they individually text you, the message is sent as an SMS. In the group chats, the messages are sent as MMS.
I also never had this issue on my S7, its just started happening when I switched to an S10. Still looking for a solution.
I've had this issue for just over a year now. I can say that I've spent countless hours attempting to research a solution to the issue. I've been unsuccessful. I can also say that I've contact multiple Samsung Service Reps as well as Service Reps from my mobile provider and have been told the same thing. They are pointing the finger and one another and won't escalate the issue up the chain to find a resolution. I keep getting told that this is an issue across all devices which it isn't, it's mostly unlocked devices and from what I personaly know its specific to a certain carrier. I've also been told to just use a 3rd party app like google messages, etc. This has resolved the issue. I am not sure why Samsung can't take note of these threads and the hundreds/thousands of comments and push some type of software update to the messaging app and or work with carriers to resolve this issue. I personally have used Samsung devices since the S3 and loved the devices until now. It's a shame that I bought a great device and have to use a 3rd party messaging app to avoid an annoyance like <subject; no subject>.