This is after a CMR 126.96.36.199 "wipe data/factory reset" has been performed. I was having the issue with all my apps restored from TI and decided to back up.
Next step is to go back to my pre-TC and try Sense again. If it still behaves that way there, there are more problems.
I came across this scenario when trying to resolve a 3G connectivity issue once WiFi is used. I can never use 3G unless I force a restart.
I have made a backup of the "wiped system" if that image will help with tracking the issue down.
Was very repeatable until...
I removed the battery. Stable without enabling WiFi
Enable Wifi -> Turn On Airplane mode -> Turn Off Airplane mode
Must have been something hanging on from all the flash/restores?