[Timocop]

There are serval things you're doing wrong here:
1) You cant set spawn locations with z_spawn, there is no argument for it.
2) Why are you creating fake clients to execute a command? Get a random client instead.
3) You should use z_spawn_old instead, z_spawn seems broken in special cases (like z_spawn auto doesn't work at all).
4) In some maps or gamemodes (versus) VScripts may interfere with spawning use Director Unlocker to uncap the limits.

PHP Code:

#include <sourcemod>
#include <sdktools>

int g_lastSpawn;

public void OnPluginStart()
{
    HookEvent("player_spawn", OnPlayerSpawn);
}

public void OnPlayerSpawn(Event event, const char[] name, bool dontBroadcast)
{
    int client = GetClientOfUserId(event.GetInt("userid"));
    
    g_lastSpawn = client;
}

void SpawnInfected()
{
    //Get random client to execute command.
    int client;
    for (int i = 1; i <= MaxClients; i++) 
    {
        if (!IsClientInGame(i))
            continue;
        
        client = i;
        break;
    }
    
    //If no client was found, we should abort.
    if (client < 1)
        return;
    
    //Spawn infected
    //Make 'name' static, keeps it in memory so it doesn't need to initalize everytime. Doesn't change anyways.
    static char spawn[][32] = {"charger", "spitter", "jockey"};
    for (int i = 1; i <= 6; i++)
    {
        //Set the it to -1 so we can check if the spawn was successfull or not.
        g_lastSpawn = -1;
        //z_spawn spawns an infected, which executes player_spawn in the same frame and fills the g_lastSpawn variable with its index.
        //If you want to spawn them automatically use "z_spawn_old auto" instead. Without the teleport below.
        CheatCommand(client, "z_spawn_old", spawn[GetRandomInt(0, sizeof(spawn) - 1)]);
        int infected = g_lastSpawn;
        
        if (infected > 0) 
        {
            TeleportEntity(infected, pos, NULL_VECTOR, NULL_VECTOR);
        }
    }
} 


Originally Posted by Halt Perhaps you could try PHP Code: SetCommandFlags("z_minion_limit", (GetCommandFlags("z_minion_limit") - FCVAR_CHEAT));  Changes the command flags.

That makes no difference. And you using it incorrecly, use bitwise operators for flags.