Flap Load Relief Limit Boeing 737
I was recently informed, by the Flight Safety Officer that I had exceeded the flap 40 limit, and as a result the flaps had retracted to flaps 30. The Captain and I had no knowledge that this happened on the flight and we were both quite shocked, I would like to think that if I had exceeded a parameter I would at least know about it, and if I did not spot it the Captain would. Is it possible that the flaps could have blow back due to gusts? I know the limit is 163 knots on the NG, but we were no where near that speed. I am a little confused as I always consider myself to be a cautious Pilot. Is this exceedance considered to be serious?