Thanks for the sugesstions so far. The behavior changed, the blinking stopped for a while, and then came back and then stopped again. I was advised by the official service guy to bring it in for service, but he did not think it was critical to keep me from using it.
Then the exhaust header split, just above the oxygen sensor. After i got this repaired, there have been no more blinking. I suspect that the header was cracked all the time, the exhaust noise is much lower now. Maybe this had something to do with the error indication, i do not know.