No matter what weapons they used, modded or not, different ammo types, melee, they can cause status effects to one another ( bleeding) but can't deal damage.
Turrets won't shoot at enemy players either, no matter the settings
PVP is enabled, friendly fire is not ( we even went to war in the factions menu to be sure )
What about this value
#DamagePvpMultiplier: 0.4
We removed the #, nothing changed
It's worth noting, that we launched the server in PVE mode accidentally at first, and then switched it to pvp without wiping. Is that the source of the issue?