I was playing assault. We were 30 seconds into the game, Then host left and host migration started. After new host was found, ( dont know who got picked ( maybe me? )) my accuracy was increased to the same amount as in overtime. ( no, overtime didn't start, i checked the timer Don't know if this was the same for other players, since they didn't have any microphones :/ Just wanted to share this
If there was another assault player in the game, you might have 'taken over' his character. This happened when I was playing with a friend. My buddy took over my tank, upgrades and all, and I ended up on some random Assault player (on the other team I too I think)...
AFAIK you get reset to the default class meaning you lose all of your custom endorsements. It is very hard to actually test this due to most host migrations failing but the only time you get reset is when you switch teams. Of note is that I use a silver Armor endorsements on my Assault and after migrating I was dying to an Assassin's front grapple, something that would not happen if I still had my silver Armor endorsement.
Endorsements sometimes do not travel correctly on host migration. When you die, just change your class once and you'll get the correct endorsements again.