I have the same issue with one of my Xenons... I did the OTA flash, then it goes through the blinking magenta and eventually goes to breathing cyan and is running user code OK (as indicated by the heartbeat on D7 LED). But there are no online events in the console for it and after about 2 minutes of running, it does an SOS-7 blinks-SOS, then reboots, repeat. It won't register any variables or functions either.
EDIT: Don't forget to target the new OS version when switching to another device in the IDE. Seems to have been my problem. After re-flashing and making sure the correct OS is selected, it flashed, came back online and is fairly solid right now.