Even opening up the app and checking sometimes won't force me to get new messages. If I hit the refresh button on Google voice about 3 times then sometimes it'll force it to finally receive the message.
Wifi works fine though, I can surf the web, stream music, watch youtube, update apps perfectly. Never have a hiccup or stutter and never had this issue until I updated to KK. Before I flashed KK, I did a backup of my apps with Helium and restored them. I wondered if that could be the problem. Not sure why it would effect the messages I receive on Hangouts or Google Voice and nothing else though.
This is the rom and procedure I used, going from stock 4.3 rooted to KK.