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 
Discussion
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