I had a second look, it looks like Grump may have braked early, or mistaken that chicane for another turn, its difficult to tell from this. We can see that Grump didn't have much time to get a good setup, his car was quite unstable, so breaking early to avoid going off himself. but at the same time, perhaps communitation may have been key here.
This chicane doesn't require one to brake, , and if you need to, not a lot. I slow down going into the chicane by gearing down, perhaps a faster car would have to brake. So I can understand Andy's frustration here, and well done to andy for avoiding a nasty incident even if you yourself went off the track.
This situation could be analysed further, so I'd like to see feedback from everyone what they think of this situation, including Grumpp.
In a situation like this, when I'm close to an opponent, I may decide whether or not to take a different racing line. This fast chicane is very hard when you are not on the race line, so perhaps also tapping the breaks to get a slightly slower entry and get a faster exit as you can afford to do so. This is a risky corner for overtaking either way.
Regardless of what happens, we need to communicate to each other, this is why we have TS., including this.
Well Done Andy for taking the win in race 2, you had a couple of unlucky incidents in race 1.