pretty sure its not hardware related because it doesn't happen on all routers/networks. If you've only tested it on one or two then try on a couple others and see. for me it only occurs on one or two out of about a dozen wifi networks
My colleagues have the same One X, they never reported anything and not even in office, while for me it does not work :/
I would say that this issue might not be easily noticeable to a common user ( at least before the JB update). As said by the OP, it is very much noticeable after the JB update.