If you're experiencing no other symptoms, I'd be inclined to attribute it to neurological sequelae from your brain injury.

[With humans anyway, but come on, this is Mass Effect, the most exotic it gets is a writer looking up amino acid chirality and then not quite understanding how it works.]

You should certainly go to the hospital and have your frontal lobe imaged, but the fact that the ageusia is transient and you're displaying no blatant cognitive deficits or psychological disturbances is encouraging!

[She's so perky.]