Spawn option in track file?

[Preziplier]

Hi all, I was looking through my track files from last night to find a dogfight to show a buddy and the replay file gives me an option to spawn in the beginning of it? I tried spectating but no players ever spawn and it just plays out like a running game with just AI. then I tried taking the slot i used during the actual flight and it acts like its an actual mission i've spawned into. I'm not sure what's going on but if anyone has any insights id appreciate it