Heya gents - bit of an issue leveling thought perhaps someone could shed some light on whats going on.  

Anyhow, In my example I'm playing a War-forged character.  Starting out at 1st level Fighter I was able to get to 3rd until the oddity occurred. In the process of leveling up to 4th, going through the level-up! process and coming to the Feats the right window had what seemed to be a 'blank' feat with an icon of a sword listed.  I'd select my available feat which would then added it to the list, I'd get the summary of level, HP's gained, feat gained etc, click 'OK' then it would revert me back to level-up thus going through the whole process again ( I've checked to make sure I meet the requirements as well - unless I'm missing something ).

So...I decided to switch to 1st level Barbarian as another class and it let me do that but I've had to take it another few times - currently I'm 3rd level  Fighter / 5th level Barbarian (wont let me take additional fighter levels)

*we've noticed this happening for another player in our group as well where he's unable to advanced in Fighter (half-ogre) I believe but any additional details on that I'm not sure and it's forced him to select another class.