I had a dropout on Richmond today, right after Governor, right before the sprint. Me and two others were about to race for third place when suddenly their avatars disappear from my screen.
I gave up immediately, but could I in theory have launched a long sprint and possibly won it on account of them not being able to see my avatar? Does the app store the exact power data locally, and then upload it when it regains connection? Or what actually happens in these cases?
You lost the network connection to Zwift’s servers.
Yes, but what happens upon reconnection? I came in ahead of a guy that was 3-4 sec behind me, but behind the two in my own group
If you regained connection:
If a group of 2/3 were in a sprint, it’s a safe assumption one or two people were in draft of a third, and would or could have floated and overall speed would increase.
When you dropped out; that means you go solo, and have zero draft benefit.
So unless you could match the power of two sprinters working together (which generally, unless you’re in the wrong cat is probably an unreasonable assumption; pace speeds increase a significant amount when drafting)… probably not.
In theory is it possible if you regain connection? Absolutely. Is it realistic to expect that outcome? Not really, no. In fact, if there was another group behind you, they would get the draft benefit as well and likely push through where you “are” in relation to their position, except again, you’re the one not getting any draft benefit, so your speed would drop off a cliff, while anyone around, would only increase.
If you don’t regain connection:
That was a good workout; but that’s all it was. Your results won’t count, as it became a ride, not an event; as you were technically not there at the finish line during the event.
The win would have depended on the others slowing down towards track stand pace (and not knowing that I was doing 400 watts ahead of them. Otherwise, yes, completely agree that it was unlikely to win third.
And Zwift is always a good workout 
i had connection problems for a few days a while ago and what happens is you stay in the event, but for the time you’re disconnected you lose draft. if you’re disconnected right before the line, you also lose the result too.
i had this happen to me on the line in a zrl race and they were kind enough to reinstate my FTS and FAL points after i showed them my dual recording and strava data but the finishing position and zwiftpower entry couldn’t be retrieved