To clarify, being too much like a student can mean one of the following:

* insistent on being "right" rather than flexible/diplomatic
* (at workplace) passively waiting to be assigned "homework" rather than actively participate
* (at workplace) overestimating what they can do with the knowledge gained at school
* being too much of an idealist/perfectionist
* ....

Roughly speaking, anything that's related to the *naive* aspects of being a student can fall under this list. I know it might sound a bit vague, but you can think of it just like "childish" as to "child" and "girlish" as to "girl". However, as far as I searched there is no such word as "student-ish", so does there exist a word that means "student-ish"?