Help Needed: Clerk-Supabase User Sync Issue in React App

Hey fellow devs!

I'm hitting a wall with an authentication sync issue between Clerk and Supabase in my React/TS app. Could use some expert eyes on this problem:

The Issue:

When users sign up or log in, I'm getting this error:

Authentication error: Supabase connection failed: invalid input syntax for type uuid: "user_..."

Sometimes followed by:

Error creating/updating user: new row violates row-level security policy for table "users"

My Setup:

Deployed a Supabase Edge Function (sync-clerk-user) that receives Clerk webhooks when users are created/updated

Function is designed to use the Supabase service role key to upsert Clerk userIDs into the public.users table

What I've Done:

Successfully deployed the Edge Function using supabase functions deploy sync-clerk-user --no-verify-jwt
Set up the webhook URL in Clerk's dashboard
Confirmed the function deployment shows success in terminal output
Started the local dev server and tested signup/login

What's Puzzling Me:

Despite having the webhook setup apparently correct, the app still throws the UUID error - suggesting that either:

The webhook isn't being received/processed correctly
The function has a runtime error I can't see
My client code might be trying to access Supabase resources before the sync completes

Questions: