Oh no, that is indeed a regression and an oversight on my part. I re-added the Alchemist's Pouch in Hardmode after introducing the Wooden Backpack, thinking it made sense now that Hardmode has inventory slots. But I completely forgot that Leather still isn't available in Hardmode. That should be fixed now!
As for the Lorestone entries unlocking with the blueprint, that's actually intentional. Since blueprint discovery already reveals the item's name and effects in the crafting menu, I felt it would be odd for it to still show as "???" on the Lorestone. I also wanted to avoid creating 2 unlock states on the Lorestone (blueprint vs crafted), as that would complicate the system more.
Thanks again for the input! Glad to have you back :)