When I get this on my 850 turbo, it has usually meant time to do the O2 sensors, so I agree with you on that diagnosis.

However, I tend to reset (as you did) and wait for reoccurrence.

Your reoccurrence seems to have come a lot sooner than mine did. I think it would go maybe a week or two before it would reoccur. (It takes a while for the ECU to decide that an O2 sensor is lazy, they drift slowly.)

Since yours seems to have come on suddenly, and reoccurs quickly, that makes me think vacuum leak. Something broke or split. I'd look for something like that first, then replace the O2 sensors if a second, close look didn't reveal any leaks.

As you know, they age together. You could replace just one, but the other will follow soon after, so I usually do both together just to minimize the hassle.

Hope this helps!

Roger