Should she really be kicked out, though? This might be a major psych problem for a Nepleslian or even a Minkan; but we're talking about a built Neko here. Three years old, life is only Star Army; no one to tell you how to spend your free time. So long as it doesn't interfere with ones' duties, Star Army typically allows all sorts of debauchery off-duty that our current military would frown upon. Yamatai's sexual freedom is worth mention here. In such a liberal society, is it really such a problem when these things are practiced off-duty? What if some otherwise perfectly capable young Neko were to save up her money and request leave once a year to go on a vacation out to Ether where some fancy Nepleslian cigar shop is set up by one expat or another; just so she can dabble a little in the expensive tastes of another culture? It would be pretty hard to frown upon that.
"Yeah, but..." You'll go on to argue, "This is an issue that affects her performance; as she's doing this on the job and suffering these withdrawals on the job."
I'm glad you hypothetically made that argument to me, because it gives me the opportunity to respond to it should it be your actual argument. This is a Nekovalkyrja we're talking about, here. She's got that whole 'masterpiece of biotechnological research and development' thing going on. You don't really have a problem so long as you can order her to stop having withdrawals. Which you can; because it's basically like unchecking the box in the UI, isn't it? Other Nekos turn off their pain all the time; why should this be any different? Perhaps a bit of counseling would be in order, to let her know that she isn't meant to be intoxicated or suffering withdrawals while on duty.
"If you want the shakes and the auditory hallucinations, it's none of my business." You might say, "But you absolutely won't be sitting here on my bridge with them."
Furthermore, have we even given any thought as to why a character might allow her body to give her those feelings? Certainly we try to ensure that Neko have no identity crisis; but when you've been born and bred as a tool of war for an Empire which only recently gave you true citizenship, there've got to be some big questions in your giant perfectly-efficient computerized head somewhere, even if you don't really think about these things. Perhaps it's out of a sense of pride. 'If this is what normal people have to endure, then I won't be spoiled if I endure it, too.' Maybe an attempt to build strength of character. 'If I can overcome this, I will be better-prepared for adverse situations I have no control over.' Perhaps even, a bit of misogyny?
In fact, even if the character was simply making a thoughtless mistake, she could cover it up but saying one of the two things I already mentioned and make herself look like quite the soldier. Compounded with the fact that such a handicap can (because of her awesome Neko body) be looked at as something so simple as a thoughtless mistake, this reaction seems off to me. Why work so hard to make Nekovalkyja such a powerful, indomitable sisterhood when you can so easily dismiss one of them for a problem that'd be easily solved?
With this argument before you; I beseech you-- Place yourself in the shoes of the superior officer. Would you still have her thrown out of the gang?