Perhaps its just me, but I've just had the strangest thing happen. All the work I've done in the last 4 hours for a map I've been working on is gone. I had finished putting in the spawns and was putting in respawn zones and objectives for each gametype. After finishing each gametype, I saved the map twice. I even had to back to other gametypes a couple times changes things and saved them as well. After finishing, I renamed the map. However, when I went to play it, nothing but Slayer worked. When I went back to Forge every single thing from the last 4 hours was gone; spawns, zones and objectives all gone. Everything from before that 4 hours was fine; but anything else had been removed for some reason. Am I going insane, is this an actual problem in Reach?
There's a chance that when going back to modify slayer or an early gametype that you worked on, you somehow loaded an earlier version of the map before you made it compatible with other gametypes. When you saved the map in that early game mode, you might have saved over the version of your map with all the other gametypes ready.
Even the earliest version I went back to was CTF. So even if that had happened, the CTF stuff should still be there, as should the basic respawn points.