Indeed, I had opted out of Normandy, SHIELD studies & co after the Looking Glass/Mr. Robot promotional ad fiasco.
Tentatively re-enabled, it's now 2 hours since the announcement but I haven't received the preference flip study yet.
A couple more hours before my fox's lastUpdateTime rolls around and my extensions get disabled, patiently waiting to see if I'll have to take manual action!
Edit: Funny, my app.normandy.run_interval_seconds was set to 24h for some reason, the new default seems to be 6h. I wonder how many people are also in that situation.