The Issue:

I wanted to create a feature where the bot sets a certain prefix before the Nickname fitting my discord server theme if a user decides to change it. I'm allowing the users to change their Nickname, i just want to make sure the prefix stays inside it. This code should detect, when a user is changing its nickname to something that doesn't contain the prefix. Then it puts it right back in front of the new Nickname they've set. But somehow if i run the bot, the event registers, but doesn't fire the first time i change a nickname. If i change it again, suddenly the event fires and the nickname gets changed. I believe there's nothing wrong with my code, but rather something with the API.

My code:

import { Client } from "discord.js";

export default function (client: Client) {
    console.log("EVENT REGISTERED!");
    client.on("guildMemberUpdate", async (_, newMember) => {
        console.log("EVENT FIRED!")

        const prefix = '🔥';
        const currentNick = newMember.nickname ?? newMember.user.username;

        if (!currentNick.startsWith(prefix)) {
            const newNick = `${prefix}${currentNick}`;

            await newMember.setNickname(newNick);
            console.log(`Nickname fixed to: ${newNick}`);
        }
    });
}

Infos about my coding setup:

• I'm using Typescript, that's why i imported the Client-Object just to specify the type of the function Parameter.
• The function is being ran once the client is ready
• I've enabled all the necessary Gateway Intents inside the code and Privileged Gateway Intents.
• The bot also has all the necessary permissions to do all of this

1- Enable the right intents

const client = new Client({
    intents: [
        GatewayIntentBits.Guilds,
        GatewayIntentBits.GuildMembers
    ]
});

2- Use partials if needed

const client = new Client({
    intents: [
        GatewayIntentBits.Guilds,
        GatewayIntentBits.GuildMembers
    ],
    partials: [Partials.GuildMember, Partials.User]
});

3- Check nickname changes explicitly:Instead of just listening for every update, compare oldMember.nickname` vs newMember.nickname

**example **

import {
    Client,
    GuildMember,
    GatewayIntentBits,
    Partials
} from "discord.js";

export default function registerNicknameHandler(client: Client) {
    console.log("EVENT REGISTERED!");

    client.on("guildMemberUpdate", async (oldMember, newMember) => {
        // Only react if nickname actually changed
        if (oldMember.nickname === newMember.nickname) return;

        console.log("EVENT FIRED!");

        const prefix = "🔥";
        const currentNick = newMember.nickname ?? newMember.user.username;

        if (!currentNick.startsWith(prefix)) {
            const newNick = `${prefix}${currentNick}`;

            try {
                await newMember.setNickname(newNick);
                console.log(`Nickname fixed to: ${newNick}`);
            } catch (err) {
                console.error("Failed to update nickname:", err);
            }
        }
    });
}