It’s a special rule for private channel openings.
…which people should do anyway
Indeed with LND you have to do a lot of mental gymnastics just to open a damn channel.
I don't know how nostr:npub1v4v57fu60zvc9d2uq23cey4fnwvxlzga9q2vta2n6xalu03rs57s0mxwu8 did it in Blixt wallet that is not requiring the anchor reserve with LND node.
Discussion
aha TIL, so that's why even if I disable the option in lnd.conf and I open public channels, it is ignored and the anchor is still in place.