So I happened to finish the monthly challenge at the same time I finished the Spartan-IV specialization. At the end of the match, I got the match experience and a message telling me to pick a new specialization. I assumed that the extra 18k from the match and monthly challenge would be applied to the specialization that I decided to pursue. Because normally when you get more experience than you need for the next rank, it is just carried over. But after selecting the Rogue specialization, it showed that I had 0xp in that specialization, so 18k of experience had just disappeared. Now I’m wondering if this is an issue/bug or if the experience does not carry over to the new specialization/rank. Hopefully someone can explain this to me, so I can avoid randomly losing a large chunk of experience again.
Finishing a specialization counts as hitting the maximum rank, until you choose a new specialization. So any experience earned after finishing a specialization will not be received, unless you begin a new specialization. Finishing a challenge for 10k xp when you only required 5k xp to get to [Specialization] 10 will result in 5k wasted xp.