MissingSecret SvelteKit Template

[LordMerc]

Environment

Github online editor,
Deployed on Vercel

Reproduction URL

https://github.com/nextauthjs/sveltekit-auth-example

Describe the issue

I am using the template, only changed the .env to have secrets and changed the kit version to ^1.5.0
I am constantly getting the error i am MissingSecret even though all 3 of the standard secrets are filled and valid.
I am not able to find any topic on this or solution.

How to reproduce

Fork the template
Fill .env
Change package.json kit version from latest to ^1.5.0
Deploy to vercel

Expected behavior

Continuous failing with error MissingSecret.

[LordMerc]

I've seemed to have fixed it by transferring the .env over to Vercel's environment variables and just using process.env,
any reason why sveltekit did not register env?