You mean the small exp reward you get every 20 sceonds or so when you are standing next to CP at a contested base? If yes then I dont think it will have any effect on the game either way.
Bug. That disappeared during a hilarious merge of old redundant code subtly breaking at least a dozen unrelated things in the last main patch.
i get defend XP sometimes, sometimes not. I don't recall getting cap guard XP anymore. I thought the defend and cap guard XP was positive and encouraged randoms to hang out on the point. Dev should bring it back.