invalid value for parameter "default_text_search_config": "public.pg"

I try to execute this on a very simple table, in a production database:

alter table product.product add proc_order int8;
create index idx_product_proc_order_status on product.product(proc_order
nulls last, product_status_id /* this has type uuid */ );

and I get this error:

SQL Error [22023]: ERROR: invalid value for parameter
"default_text_search_config": "public.pg"
Where: while setting parameter "default_text_search_config" to "public.pg"
parallel worker

I have been using this database for many weeks now, and never got a similar
message. I don't understand how the creation of an index on an int8 and an
uuid field is related to full text search.

Thanks,

Laszlo