Tailored Legendary Pack  

 

I bought both books and scribed them (Guide to Transcendent bags and 'Extradimensional Luggage: A Guide' ). I tried combine in experiment, I still get same mesg - "This seems correct but something is wrong. Perhaps you need to know something more in order to combine this"

I noticed I have only 1 recipe in the list for a heavy bag. I then went to gain tailoring skill (now 54), and still just 1 in list. Bought both books again and scribed them, still only 1 recipe shows. Tried combine and still same mesg - "This seems correct but something is wrong. Perhaps you need to know something more in order to combine this"

and I made this combine on my other character just minutes before to test it. (though he is a 300 skill tailoring with many books bought)
It looks like this combine wont work with newly made characters, as they seem to be missing something that is gotten over time as a character gains skill.