Mine has the little x in the wifi bar.I usually notice it after waking the Kindle Fire Hd. It seems to go back to normal after a minute or so.
Wifi functions as normal throughout so it's not a problem for me.
Im on 7.2.3
I have the same issue although every now & then it will lose connection, a quick disconnect & reconnect usually sorts it out, hope it can be fixed, seems the only downside to rooting at the minute.
KFHD "7 - Software version 7.2.3