Bugs or missing features, or both:
Normal Knight sword is missing. Knight Commander skin is missing. Lighting does not reflect off plating. Lights do not conform to skins like the thumbnail from Halo 4 itself. Helmets are not segregated from body types. Second-back wings cannot be posed with joint tool. Lights not recolourable with advanced color tool. Waist/hip area not posable, meaning legs cannot walk in one other direction (sideways walk while front facing you). Skull not posable. Large elbow-spike-things-that-resemble-fins not posable with joint tool (not the weapon grips). Battlewagon thrusters don't exactly override the normal thrusters.

https://steamhost.cn/steamcommunity_com/id/Koldraxian_Legion_732/screenshots/ is where you'll see proof.
Phanto I pray you are on this matter ASAP as it will also affect the SFM counterpart. You may want to ask the Facepunch group regarding the Knights' textures, etc... so you can correct the faults present.

https://facepunch.com/showthread.php?t=1250225&page=69 is aware of your Promethean Knights, Phanto.