Bug: The dropped player ammo still remains enabled with $Pref::Server::TT::DisableAmmoItems enabled.
Fix: move lines 1-19 from ammo_unified.cs to the bottom of item_ammo.cs
Dropped player ammo is supposed to be separate from the ammo pickups that show up in the item list and isn't controlled by $Pref::Server::TT::DisableAmmoItems. The name probably isn't clear enough, it should be something like "disable ammo spawns" instead.
Drops are controlled by $Pref::Server::TT::PlayerAmmoDrop, $Pref::Server::TT::BotAmmoDrop, $Pref::Server::TT::PlayerNadeDrop, and $Pref::Server::TT::BotNadeDrop. There's currently no way to disable the datablock itself, but that could be changed.