Frost Death Knight - Burning Legion Legendary Blades of The Fallen Prince

Website is not recognizing (Gear Check - GC) Death Knight Rune of The Fallen Crusader (FC) as being assigned for enchant to offhand Blades Of The Fallen Prince after add on has been imported and posted as per directions and procedure for requesting GC to the website.
Add-on Recognizes that FC is assigned to offhand weapon.
Which should I believe?
Add-on or Website?

I’d have to double check… runeforges/enchants on the legion legendaries was always a huge pain, since the off-hand weapon doesn’t actually “exist” in your bag. I’m not sure if we retired the code that handled that or not because it’s a couple expansions out of date now…

If you could post the text here that you are copying from the in-game addon to the website to load your character, we could take a closer look.