I'm downloaded the new version and theres a very weird bug.
I added some enchanted books, and anvil to my inventory.
Then i was combined fire aspect book to a diamond sword.
and theres a feather falling book at my inventory then i tried to combine with the enchanted sword and it worked and tried with torch,arrows,anvils,etc
theres screenshots demonstrating this bug
and in the client console that text appears:

Naming an item only, cost too high; giving discount to cap cost to 39 levels