I read in a previously closed issue that the Apex enchantments will disappear if they are obtained illegitimately. However, in my single player world, when I used enchantment fusion to create a Blessed Blade II book, then added it to my sword with an anvil (all legitimately), it still made the enchantment disappear. It worked when I performed the enchantment fusion directly onto the sword rather than going through the book + anvil. Could there be some clarity provided for this? I'm not sure why obtaining the enchantment on a book, then adding it to a tool with the anvil, would be considered illegitimate.

I play on a server, and with me the enchantments also disappear, I have prints showing that the enchantments were not obtained illegitimately.

You need to apply it not via book. That will not transfer the "validity bit"

I understand, the difficulty is just to collect the items to perform the fusion and then the enchantment disappears, thank you for responding :)

now it doesn't disappear, thank you very much 😎👍