Swapping to WHM caused this pop up

Time: 2016/12/30 19:50JST
Frequency: Once
World name: Behemoth
Character name: Mayoyama Nakata
Retainer name: NA
NPC name: NA
Monster name:NA
Class/Level: WHM60
Party or solo: Solo
In-game time: around 16:30
Area and coordinates:East Thanalan 13.8, 24.3
Housing: NA
Steps: Swapped from DRG to WHM using the gearset macro on my hotbar
1. The game then came up with the error "Shire crook registered to this gear set cannot be equipped. Replace it with a Shire crook?
2. Swap to SCH, then back to WHM, no message. Swap several more times to other classes and back to whm, no message

I have been using whm all of today and this message hasnt popped up, and I haven't made any changes to my gear.

Screenshot: http://imgur.com/a/V7bTM