I Feel Your Pain
I really do, because it happens to me, exactly like you, randomly, not consistent, except that it happens to me when going from the big chain ring to the small. Once out of every 10 - 15 times, using the same gear ratio each time, it'll drop the chain on the inside. Then it'll do it again the next time, then it won't for another 15 shifts. Don't listen to the people who say you need to find a better mechanic or say it's obviously an adjustment, bad limit screws, etc. It's an apparent flaw inherent with SRAM. I do like the poster who said screw it, I switched to Shimano, never had a problem. If I had the money to do that I would.
My adjustment is spot on, a frog's hair from touching the inside wall of the FD, that's not the issue. It was installed with the tool, it's perfect. My firmware is up to date. I finally figured out what the issue is, and it's not adjustments/alignments, it's the derailleur. When you're in specific cogs in the back (I think it's the biggest and smallest) and shift the FD, it shifts twice, once to move the chain, then once to settle back to the correct alignment. When you're in the middle cogs in the back, it only shifts once. I guess it doesn't need the over adjustment to get the chain to move unless you're executing a much larger ratio. I might have that reversed, I'm not watching my bike right now. I watched it very intently in the stand with my own eyes. Middle cogs in the back, shift high to low, one shift, perfect. Keep doing it, multiple times, all perfect shifts. Then it happened. Shift (using the button on the derailleur), bang, two moves, throw the chain. Put it back on, same gearing ratio, shift, one shift, perfect. It's like it's randomly confused that the rear is in the highest or lowest cog, when it isn't. Sometimes it will do it twice in a row, and then work fine for the next 10 shifts.
To me, this is a firmware issue because it randomly moves twice using the same gearing ratio, when it should only move once all the time in the same gear in the rear. 10 - 15 times in the same gear it makes one shift, then for some odd reason it decides to shift twice like the rear is in the extreme cog, which it isn't, and it throws the chain.
It's disappointing to hear that a new FD didn't fix it. With enough people saying this happens to them as well, and my own personal experience watching the derailleur randomly shift twice and dropping the chain, and then the other 10 - 15 times it shifts once with a perfect shift, you can't adjust that out. And I'm really frustrated with it.