Hmmm, I have seen this mentioned on the posts on the Cyanogen Nexus ROM thread on the XDA Developers forum (hit on the link to it from the CyanogenMod site - the ROM page). What I suggest is that you do a keyword search on this thread I have mentioned for your symptom - you may be best signing up to XDA & posting for help there......
If you are having problems with your wifi without having successfully ran a custom ROM (and are therefore, still on the stock version), then you may well have an issue.
My best advice is to post a question on XDA and you will get the best answer from there honestly. A bit beyond my experience/knowledge - you may well be advised to reflash the Stock ROM but I am not sure. Post to XDA and they seem to be pretty quick to respond (plus there are loads of techies on that forum - a good thing!).