Tiktok Auth sending client secret on login

typescript:auth.ts
import { betterAuth } from "better-auth"

export const auth = betterAuth({
    socialProviders: {
        tiktok: { 
            clientSecret: process.env.TIKTOK_CLIENT_SECRET as string, 
            clientKey: process.env.TIKTOK_CLIENT_KEY as string, 
        }, 
    },
})

typescript:auth.ts
import { betterAuth } from "better-auth"

export const auth = betterAuth({
    socialProviders: {
        tiktok: { 
            clientSecret: process.env.TIKTOK_CLIENT_SECRET as string, 
            clientKey: process.env.TIKTOK_CLIENT_KEY as string, 
        }, 
    },
})

typescript:auth-client.ts
import { createAuthClient } from "better-auth/client"
const authClient =  createAuthClient()

const signIn = async () => {
    const data = await authClient.signIn.social({
        provider: "tiktok"
    })
}

typescript:auth-client.ts
import { createAuthClient } from "better-auth/client"
const authClient =  createAuthClient()

const signIn = async () => {
    const data = await authClient.signIn.social({
        provider: "tiktok"
    })
}

await fetch("https://XXX/api/auth/sign-in/social", {
    "body": "{\"provider\":\"tiktok\"}",
});

await fetch("https://XXX/api/auth/sign-in/social", {
    "body": "{\"provider\":\"tiktok\"}",
});

{"url":"https://www.tiktok.com/v2/auth/authorize?scope=user.info.profile&response_type=code&client_key=XXX&client_secret=XXXXXXXXXXX&redirect_uri=https%3A%2F%2FXXX%2Fapi%2Fauth%2Fcallback%2Ftiktok&state=XXX","redirect":true}

{"url":"https://www.tiktok.com/v2/auth/authorize?scope=user.info.profile&response_type=code&client_key=XXX&client_secret=XXXXXXXXXXX&redirect_uri=https%3A%2F%2FXXX%2Fapi%2Fauth%2Fcallback%2Ftiktok&state=XXX","redirect":true}

import { betterAuth } from "better-auth"
export const auth = betterAuth({
  database: prismaAdapter(db, {
    provider: 'mysql',
  }),
  emailAndPassword: {
    enabled: false,
  },
  socialProviders: {
    tiktok: {
      // @ts-expect-error TikTok does not use clientId
      clientId: process.env.TIKTOK_CLIENT_ID as string,
      clientSecret: process.env.TIKTOK_CLIENT_SECRET as string,
      clientKey: process.env.TIKTOK_CLIENT_KEY as string,
    },
  },
});

import { betterAuth } from "better-auth"
export const auth = betterAuth({
  database: prismaAdapter(db, {
    provider: 'mysql',
  }),
  emailAndPassword: {
    enabled: false,
  },
  socialProviders: {
    tiktok: {
      // @ts-expect-error TikTok does not use clientId
      clientId: process.env.TIKTOK_CLIENT_ID as string,
      clientSecret: process.env.TIKTOK_CLIENT_SECRET as string,
      clientKey: process.env.TIKTOK_CLIENT_KEY as string,
    },
  },
});