This is not a bug but does not notify you that you can not have another officer at your level. I learned to not accept the officer until I had another opening for an officer.
How would that be so? Since you can use the officer and train skills from it to your existing ones. I would say it's very much a bug. The BO's SHOULD after accepting them end up in your Assignments tab. But most of them does not and just vanish instead. This has happened since the beginning of open beta.
Any chance a dev can comment on this? I know you don't know what's doing it, but do you know what you're going to do once you fix it? Are those of us who lost all the rare officers just screwed, or will you reset them like you did in OB and give us a stack of random ones to compensate for the loss?