TLDR:
Normal game modes ignore custom player-made spawn markers, even when they’re the only choice (you get spawned in somewhere default.) Only Forge game modes adhere to player-made spawn markers.
Verbose:
So this was happening during the flight I played for H3 on PC as well, but I thought it might have just been a me thing with a bad choice of game mode. Turns out I was wrong.
I’ve built a few custom maps now, and after testing them in Team Slayer game variant (not via Forge), the game completely ignores all of my spawn markers and places players in default locations on each map. These spawn locations appear random and I have double-checked that there are no spawn markers on those positions.
I’ve also tried other game modes. One of my maps has a good abundance of markers for teams of 8v8 - these are set to attackers/defenders, respectively, as well as up to 12 players in FFA (so the rest are set to neutral). The same thing happens - I get spawned elsewhere in any custom game mode, that is, anywhere except my markers, as though they aren’t there.
I thought it might just be happening on Sandbox, but it’s happening on any map when I remove and replace all default spawn markers. I’ve tried renaming the .mvar for these files and moving them out of and back into the folder, but so far nothing I do makes any difference.
Importantly, when in Forge mode (and any game mode while in Forge), the game adheres to the spawn markers. It’s only when I take the map to an actual custom game (not a Forge game) that it ignores the spawn markers.
I haven’t yet tested H2A/Reach to see if they’re also affected.