Dragoon cannot roll need on mid level gear equippable by the class.

Date & Time: August 13 2017, 2:10pm EST
Frequency: Always
World name: Balmung
Character name: Gentle Willow
Retainer name: N/A
NPC name: N/A
Monster name: The Chimera(? Just dropped the item)
Class/Level: Dragoon 40 & 41
Party or solo: Party
In-game time: ~6am ET
Area and coordinates: Cutter's Cry
Housing: NA
Steps:
1. A "Heavy" armor item that is listed as usable as Dragoon drops in a dungeon. For example, "Kokoroon's Darkscale Mail" and "Aetherial Horn Scale Mail" both triggered this.
2. "Need" is greyed out and an error text displays as, "This item is not suited to your current class or job" despite Dragoon being listed as a class that can equip it. I've included a screenshot hosted here for evidence. https://i.imgur.com/qBT8sFO.png

Connection Specs
- Type of internet connection/provider: DSL
- Modem maker/model number: Arris 902A/HC

■ PC Specs

To obtain the system information, open the FFXIV launcher and select Config → System Information → Display.

-=-=-=-=- System Information -=-=-=-=-
SYSTEM_OS Windows 10 Home 64-bit (6.2, Build 9200) (14393.rs1_release.170731-1934)
SYSTEM_CPU Intel(R) Core(TM) i7-3770 CPU @ 3.40GHz (8 CPUs), ~3.4GHz
SYSTEM_CORE_NUM SYSTEM_CORE_LOGIC 8 SYSTEM_CORE_PHYSICS 4
SYSTEM_BIOS 0508
SYSTEM_LANGUAGE English (Regional Setting: English)
SYSTEM_MEMORY 16337.570MB
SYSTEM_VIRTUAL_MEMORY 134217727.875MB
SYSTEM_PAGE_FILE 19275.570MB
SYSTEM_STORAGE C:\ SYSTEM_HARDDISK_DRIVE SYSTEM_TOTALDISC_SPACE 915.912GB SYSTEM_FREEDISC_SPACE 182.974GB
SYSTEM_DIRECTX_VERSION DirectX 12
SYSTEM_GRAPHICS NVIDIA GeForce GTX 1070
SYSTEM_GRAPHICS_DEVICE \\.\DISPLAY1
SYSTEM_GRAPHICS_CHIP GeForce GTX 1070
SYSTEM_GRAPHICS_MAKER NVIDIA
SYSTEM_GRAPHICS_VRAM 8119.938 MB
SYSTEM_GRAPHICS_SHARED_VRAM 8168.785 MB
SYSTEM_GRAPHICS_DAC Integrated RAMDAC
SYSTEM_GRAPHICS_DISPLAY_MODE 1920 x 1080 (32 bit) (60Hz)
SYSTEM_GRAPHICS_DRIVER C:\WINDOWS\System32\DriverStore\FileRepository\nv_dispi.inf_amd64_02838dee03d82b94\nvd3dumx.dll,C:\WINDOWS\System32\DriverStore\FileRepository\nv_dispi.inf_amd64_02838dee03d82b94\nvwgf2umx.dll,C:\WINDOWS\System32\DriverStore\FileRepository\nv_dispi.inf_amd64_02838dee03d82b94\nvwgf2umx.dll,C:\WINDOWS\System32\DriverStore\FileRepository\nv_dispi.inf_amd64_02838dee03d82b94\nvwgf2umx.dll
SYSTEM_GRAPHICS_DRIVER_VERSION 21.21.0013.7849
SYSTEM_GRAPHICS_DRIVER_DATE 1/19/2017 20:00:00
SYSTEM_GRAPHICS_DRIVER_LANGUAGE English
3.0
SYSTEM_GRAPHICS_PIXEL_SHADER 3.0
SYSTEM_GRAPHICS_VERTEX_TEXTURE SYSTEM_SUPPORT
SYSTEM_GRAPHICS NVIDIA GeForce GTX 1070
SYSTEM_GRAPHICS_DEVICE \\.\DISPLAY2
SYSTEM_GRAPHICS_CHIP GeForce GTX 1070
SYSTEM_GRAPHICS_MAKER NVIDIA
SYSTEM_GRAPHICS_VRAM 8119.938 MB
SYSTEM_GRAPHICS_SHARED_VRAM 8168.785 MB
SYSTEM_GRAPHICS_DAC Integrated RAMDAC
SYSTEM_GRAPHICS_DISPLAY_MODE 1920 x 1080 (32 bit) (60Hz)
SYSTEM_GRAPHICS_DRIVER C:\WINDOWS\System32\DriverStore\FileRepository\nv_dispi.inf_amd64_02838dee03d82b94\nvd3dumx.dll,C:\WINDOWS\System32\DriverStore\FileRepository\nv_dispi.inf_amd64_02838dee03d82b94\nvwgf2umx.dll,C:\WINDOWS\System32\DriverStore\FileRepository\nv_dispi.inf_amd64_02838dee03d82b94\nvwgf2umx.dll,C:\WINDOWS\System32\DriverStore\FileRepository\nv_dispi.inf_amd64_02838dee03d82b94\nvwgf2umx.dll
SYSTEM_GRAPHICS_DRIVER_VERSION 21.21.0013.7849
SYSTEM_GRAPHICS_DRIVER_DATE 1/19/2017 20:00:00
SYSTEM_GRAPHICS_DRIVER_LANGUAGE English
3.0
SYSTEM_GRAPHICS_PIXEL_SHADER 3.0
SYSTEM_GRAPHICS_VERTEX_TEXTURE SYSTEM_SUPPORT
SYSTEM_SOUND Speakers (Realtek High Definition Audio)
SYSTEM_SOUND_DEVICE_ID {C2205D98-590B-49BE-A08D-92116F6926C7}
SYSTEM_SOUND_DEVICE_NAME RTKVHD64.sys
SYSTEM_SOUND_DRIVER_VERSION 6.00.0001.8004
SYSTEM_SOUND_DRIVER_LANGUAGE English
SYSTEM_SOUND_DRIVER_DATE 11/29/2016 00:00:00
SYSTEM_INPUT {6F1D2B60-D5A0-11CF-BFC7444553540000}
SYSTEM_INPUT_NAME Mouse
SYSTEM_INPUT_REMARKS SYSTEM_GAMEPAD_AXIS 3 SYSTEM_GAMEPAD_BUTTON 8 SYSTEM_GAMEPAD_FOV 0
SYSTEM_INPUT {6F1D2B61-D5A0-11CF-BFC7444553540000}
SYSTEM_INPUT_NAME Keyboard
SYSTEM_INPUT_REMARKS SYSTEM_GAMEPAD_AXIS 0 SYSTEM_GAMEPAD_BUTTON 128 SYSTEM_GAMEPAD_FOV 0
SYSTEM_INPUT {47343740-04A8-11E6-8001444553540000}
SYSTEM_INPUT_NAME USB Keyboard
SYSTEM_INPUT_REMARKS SYSTEM_GAMEPAD_AXIS 0 SYSTEM_GAMEPAD_BUTTON 3 SYSTEM_GAMEPAD_FOV 0
SYSTEM_INPUT {47348560-04A8-11E6-8002444553540000}
SYSTEM_INPUT_NAME USB Keyboard
SYSTEM_INPUT_REMARKS SYSTEM_GAMEPAD_AXIS 0 SYSTEM_GAMEPAD_BUTTON 21 SYSTEM_GAMEPAD_FOV 0
SYSTEM_INPUT {A5E471F0-8C28-11E4-8003444553540000}
SYSTEM_INPUT_NAME USB Laser Game Mouse
SYSTEM_INPUT_REMARKS SYSTEM_GAMEPAD_AXIS 0 SYSTEM_GAMEPAD_BUTTON 4096 SYSTEM_GAMEPAD_FOV 0
SYSTEM_INPUT {A5E4C010-8C28-11E4-8004444553540000}
SYSTEM_INPUT_NAME USB Laser Game Mouse
SYSTEM_INPUT_REMARKS SYSTEM_GAMEPAD_AXIS 0 SYSTEM_GAMEPAD_BUTTON 0 SYSTEM_GAMEPAD_FOV 0
SYSTEM_INPUT {47348560-04A8-11E6-8003444553540000}
SYSTEM_INPUT_NAME USB Keyboard
SYSTEM_INPUT_REMARKS SYSTEM_GAMEPAD_AXIS 1 SYSTEM_GAMEPAD_BUTTON 1 SYSTEM_GAMEPAD_FOV 0
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

Despite being equipable by Dragoons, that piece is meant for tanks. Tenacity only appears on gear meant for tanks, since it does literally nothing if you aren't a tank.