Same Issue here, however I have noticed that sometimes the skills themselves have disappeared.The window is just blank except for energy credits and window title. The rest of the time they are just greyed out.
Ships can end up in your overflow bag if your inventory is full. Know its probably not the case here but is worth checking for others here with similar problems reading this thread.
Apologises for posting here but I don't have permission to create my own thread yet (very annoying). I've got a server side issue that effects the officer training window. It's consistently either totally blank or the skills appear but the selection areas are greyed, no energy costs appear and none of the buttons work.…