Firebase functions auth.generateEmailVerificationLink() generating link with wrong apiKey - firebase-authentication

Question

I have a Firebase functions project with dev and prod versions. There I'm using auth.generateEmailVerificationLink() to send email verification for a newly created user. Everything works well except in prod environment (testing locally or hosted) the apiKey in the link generated by auth.generateEmailVerificationLink() is not same as Firebase's default apiKey. And clicking that link I get the page with error code:
Try verifying your email again
Your request to verify your email has expired or the link has already been used
Note that when I get the link with the wrong apiKey, if I change it to the right apiKey. the verification works. So it seems the whole problem is related to the wrong apiKey in generated email verification link.
Also to note that the wrong apiKey is not random key but used in project front end for Google Maps apis.
The code itself is simple. (I'm leaving out code which creates user etc as those parts all work perfectly)
-Initializing Admin SDK:
import { initializeApp } from 'firebase-admin/app';
import { getAuth } from 'firebase-admin/auth';
initializeApp();
const auth = getAuth();
export { auth };
-Generating email verification email
const sendEmail = async () => {
const actionCodeSettings = {
// This url is working correctly, it is the same as in Firebase console
// and when changing the wrong apiKey to correct redirecting works correctly
url: process.env.DOMAIN as string,
};
await auth
.generateEmailVerificationLink(email, actionCodeSettings) // email is the email of newly created user
.then((link) => {
// generate email message with link
// generate mailOptions
// use transporter to send email
});
};
Thank you for any help
EDIT
I tested deleting that "wrong" apiKey from GCP credentials page and replaced it with another. Then running the function locally everything worked normally but the "wrong" is still in the verification email link even tho it doesn't exist anymore.
Firebase strongly recommends that if Admin SDK is used in Cloud Functions, among others, initializing the app should be done without parameters.
https://firebase.google.com/docs/admin/setup#initialize-without-parameters
For me it seems something is for some reason pulling that "wrong" and now even deleted apiKey from somewhere to usage.

Answer 1

I solved this by noticing that, unlike in dev project, Web Api Key (Project Settings>General) is different than Web App's firebaseConfig apiKey.
So I added correct permission to this Web Api Key (Identity Toolkit API is required for email verification email) found in GCP credentials and now the cloud function sends email verification emails with correct and working apiKey.