Wi-Fi error after. Jailbreaking iPad 2 4.3.3?

[sutty0000]

I've found that I've gone into a new wifi network and connected to it fine. But when I lock my iPad 2 and unlock again to check twitter etc. It stays on 3G and doesn't automatically re-connect to the wifi network I have to manually go into setting and tap in the network for it to re-connect and then it's fine until I lock it next. Anyone had this happen or know how to fix it?
Thanks

PS known networks before I jail broke work fine at re connecting