Given that you’re using the giant map mod, it’s probably the same issue as Corner maps render Hearthlings incapable of stocking stuff, which sould be fixed in the next release (should be on the unstable branch by the end of this week). If you still see the issue in that release, please upload the offending savegame.
i don’t why but also invaders are coming twice a day in multiplayer.
Invaders spawn separately for each player.