The coloring on the shoulder parts of the costumes differs when worn by male versus female characters. When worn by a male character, the leggings uniform's shoulders and the research robe's shoulders are blue; when worn by a female character, they're brown. This means that the outfits' coloring -- and by extension, how the costumes look when dyed -- differs depending on whether your character is male or female.

Here is a comparison picture showing the research robes costume worn by a female player character (on the left), a male player character (on the right), and an NPC wearing a similar outfit (in the middle). After examining several NPCs who wear the research robes (or a similar outfit), no one actually wears a variant with blue shoulders -- they're all brown. Interestingly, a promotional render for the Mages Guild pack appears to show both the male and female robes with blue shoulders.

As for the leggings uniform, a standalone promotional render shows both the male and female costumes with blue shoulders. However, in the promotional render for the Mages Guild pack, the female costume appears to have brown shoulders.

Interestingly, looking at older pictures from the Unofficial Elder Scrolls Pages, both the female research robes and the female leggings uniform appear to have blue shoulders, which suggests that the female costumes originally shared the male costumes' coloring but were later changed.

Higher-quality screenshots may be seen on ESO Fashion.

Not a huge issue, obviously, but since it just seems to be an issue with which parts of the costume share which dye channels, hopefully it will be easy to fix.