I think I may have found a bug in UEFN games related to the Player Spawner.
Issue:
If you enter a game as a team of friends into a game that equally divides players onto two teams, then the team of friends are all spawned into the same Player Spawners regardless of having been put on to different teams. The game had no players and was empty, so this may also be part of the issue.
What should occur:
Team of friends is divided equally onto teams and should be spawned in the correct Player Spawners according to their team index.
Can be tested on my island Blob King Battle (2364-4598-1319) here:
https://www.fortnite.com/creative/island-codes/2364-4598-1319?lang=en-US