Not in my case, vehicles are persistent and remain in level until they are killed off. pilot however is spawned when hop-out of vehicle, so perhaps there is something to it there. if a player hops out of a vehicle, a new character is spawned for them and they take control of it. If they hop into a vehicle, character is destroyed. (This is a bit inefficient but was quickest way to to it instead of pooling them / hiding them out-of-world somewhere).
I think that there’s a possibility that widget is destroyed and rebuilt locally before client properly sets up new pawn it receives from server. Mind you, it strikes me as a bit weird that you can’t change pawn without having to rebuild widgets anyway.
As for door thing - In that case I would just check for overlap event on Server instead of Client, since they’re both in sync anyway right, and have Server open door object. (I may be missing something here though).