I was teaching my bridge officers new skills and inadvertantly taught my Science Officer a ground skill that she already knew at a later stage (She learnt Neural Neutraliser 1 at Commander yet I tried to teach it to her at Lt Comm). Her Commander ability is now just a blank space. When I try to teach her a new Commander ability she isn't highlighted and when I hover my mouse over a new ability it comes up "Replaces unknown node" but as she isn't highlighted I can't teach her anything. I've bug reported this but should I contact a GM in game or just replace her (which I don't really want to do as I've spent alot of points on her).
I had the same Problem and had made a Ticket an an GM Request but the Answer was only some pre mades phrases, i dont become any help at all.
A Fleetmember had this with his Borg BO too, an it was the same.
It seems that Cryptic WILL NOT help costumers on this Bugs!
The BO is useless without the Skill Slot and the only thing you can do now is too make a new one.
The Bug is at the Skill assignment where some skills are not linked to the right place and so it replaces an other place you mind.
So be careful in learning new Skills to BO and check if the skill which the BO will forget is the skill he should do so.