When replying to a message that was sent by another person, it is common practice to start your response with "RE:" (short for "response") followed by the subject line of their original message. For example, if the original message had the subject line "Need help with project", you could reply with "RE: Need help with project". This helps keep things organized and makes it clear who is responding to whom.
Discussion
This is not email though. Look at the screenshot, everyone is replying to someone else, except you: it says you’re replying to self even though you’re replying to someone else. I’m wondering if it’s a bug 
It’s likely because the p tag is missing in event.tags 😉
I’ve seen this happen with replies sent from nostr:npub1plstrz6dhu8q4fq0e4rjpxe2fxe5x87y2w6xpm70gh9qh5tt66kqkgkx8j – not sure why it does that.
Have you seen that lately? Asking cause we changed whole writing post part a lot.
I see it in the code that if its reply we are adding the p tag.
But rather first asking before i will look into that more