Description of the issue:

Having problem when I want to obtain a outfitter villager. Please note that my steps are all corect( place a white banner and use a shader on it by right clicking ), but the career still cannot properly pop out.

Also, I have been tried the same actions on a minimal instance, it worked normally. So it may be some mod conflict problems since I am playing on a modpack now, named Enigimatica 6: Expert, you can find the modpack by using the link below.
Curseforge

Versions & Modlist

Minecraft version: 1.16.5
Forge version: 1.16.5-36.2.29
IE version: 1.16.5-5.0.7-143

(Modlist will be provide using several images)

Turns out if you let the villager stay in a narrow place with the specific block, sometime it will not obtain a career. I place the banner at a bigger place and it work.

Actually I think the issue is the villager cannot use a wall mounted banner as a POI, only one that is placed on the floor. I think this should be re-opened as either needing better documentation, or a fix to allow wallmounted banners.