Was it corners 9 and 10?
If the F1 game is anything to go by those corners are so easy to go a little wide on. There's so much run off and no (physical) punishment for using some of it. If it's too big an issue they should put a gravel trap in them like they have at 4, 6,7,8.
Running wide at 9 and 10 is quicker than staying on the track and gives you more speed into the next lap as well. That's why two laps were deleted from anyone who exceeded them in qualifying - because you gain an advantage on lap you're on and the start of the next one.