Yes we had roughly the same error. Our Zitadel version is 3.3.0 and we are self-hosted using Nginx as a proxy. I also properly set the .env.local variables for ZITADEL_API_URL and the service user PAT.
The error arises when running the login UI locally while trying to connect to our self hosted Zitadel. We haven’t tried deploying the login UI yet with HTTPS.