Subject: PostgREST schema cache permanently corrupted after DROP + CREATE FUNCTION — NOTIFY reload has no effect

# Bug report - [x] I confirm this is a bug with Supabase, not with my own application. - [x] I confirm I have searched the [Docs](https://docs.supabase.com), GitHub [Discussions](https://github.com/supabase/supabase/discussions), and [Discord](https://discord.supabase.com). ## Describe the bug After dropping and recreating a PostgreSQL function, PostgREST permanently returns error **42725 (ambiguous function)** on all RPC calls to any function with a `RETURNS SETOF "tablename"` signature. Neither `NOTIFY pgrst, 'reload schema'` nor a full project restart clears the corrupted schema cache. ## To Reproduce 1. Have a working RPC function: ```sql CREATE OR REPLACE FUNCTION public.get_fund_detail(p_slug text) RETURNS SETOF "Funds" LANGUAGE plpgsql STABLE SECURITY DEFINER AS $$ BEGIN RETURN QUERY SELECT * FROM "Funds" WHERE slug = p_slug LIMIT 1; END; $$; ``` 2. Drop it and recreate it (required when changing return type): ```sql DROP FUNCTION public.get_fund_detail(text); CREATE OR REPLACE FUNCTION public.get_fund_detail(p_slug text) RETURNS SETOF "Funds" ... ``` 3. Call `POST /rest/v1/rpc/get_fund_detail` → **400 Bad Request**, `proxy-status: PostgREST; error=42725` 4. Run `NOTIFY pgrst, 'reload schema'` → no effect 5. Restart project via dashboard → no effect 6. Create a **brand new function** with a different name, same signature → still 42725 7. Create a brand new function with a different name **and** different return type (`RETURNS json`) → still 42725 Functions that were never dropped continue to work normally throughout. ## Expected behavior After `NOTIFY pgrst, 'reload schema'` or a full project restart, PostgREST should reload its schema cache and correctly resolve the single existing function without returning 42725. ## Screenshots Network tab showing the error on a fresh function that was never dropped: ``` POST /rest/v1/rpc/fetch_fund_by_slug Status: 400 Bad Request proxy-status: PostgREST; error=42725 ``` `pg_proc` confirms only one function exists with tha…