These aren’t nested replies the way you’d expect from nested commenting systems, these are duplicates of replies that happen later in the conversation. The idea is that this makes it a little easier to see far-flung responses in close context of what they’re replying to.
There’s also an alternative option for this feature that temporarily hides the posts in-between replies rather than duplicating them (which moves away from the appearance of nesting). That site setting is called enable filtered replies view if you’re curious.
All that said, this is still correct.