Strangely enough I originally posted this to HN as a threadreader link, but it looks like the mods switched it to the original thread on Twitter. I can't remember ever seeing that before. Is this a new stance that HN now frowns upon threading apps?
A number of URL remappings occur automatically, and Threadreader conversions may be amongst these. OTOH, Reddit links seem to be automatically rewritten to old.reddit.com.
I've suggested YC consider running its own Nitter node for that system's UI/UX advantages.