Well that's a balance chart, not equity. So I'm not averaging down trades, but i do widen my reverse (stop) and target and also adjust the position to recover (not quite martingale, it follows a sequence after few reverses fail).
But I do emphasize consistency over the large inconsistent profit targets, so the wins are capped as you say.
What's a balance chart?
Regardless, if your largest win is $1411 and your average daily gain is in the ballpark of $50-100 the logical conclusion would be that you have had a drawdown in that ballpark which you recovered from to end the day around your average daily gain.
So, in summary, you cap the wins while not capping the losses. This seems to be the opposite of letting your winners run and cutting your losses short. So far it seems to have worked out very well, but since you brought up the subject of black swans, I suppose it's possible you'll one day won't be able to recover from an intraday drawdown and would have to realize a larger loss (relatively speaking).
I wonder if there'd be a way for you to squeeze out more of your winners, i.e., maybe scale out of your positions by letting a winner run. For example booking a profit on one contract and letting the other run with a B/E entry or similar.
Regardless, I'm not giving you any advice here as it seems to be working very well for you, but your intraday drawdown figures does raise some concern for that black swan showing up one day just by the law of large numbers.