This is not really a bug just an annoying feature in the game, where putting carpets around your enchantingtable will make in not recognising bookshelves outside the carpets.
In the images the one without carpets will give lvl 30 enchants the other will not.
Work as intended. This is not a suggestion submitting place. Use https://www.reddit.com/r/MinecraftSuggestions to post your suggestions.