I had a similar issue responding to something in /m/random yesterday, and I ended up making a new mircoblog on programming.dev (and mentioning people) instead. They saw it (and mentioned me) but I didn't get a notification and their replies don't show up even now here on kbin (I see the replies on one of their instances). EDIT: I should say the replies aren't visible on programming.dev either, not sure if that's part of it