In the first replay I saved and then watched (online game) I noticed two of the errors you mentioned, #1 and #2.
And with a player conceding there was no gamestate error but the replay shows that everyone conceded and the game ends rough 10 minutes earlier than it really did.
Funny thing is that only when I watch the replay everybody concedes, my friend who was also in the game sees the game how it really went. (He sent me the replay he saved and it still shows that the game ends at 8 min mark when watching the replay I got from him).
And to add a bit of twist the next replay I saved works perfectly despite that somebody concedes in that game too (winner and participant awards were handed correctly too).