vaccumdb fails saying function unaccent(text) doesn't exist

Hi everyone,

I migrated an postgresql instance from 9.5.4 to 9.5.21.

Unaccent extension is installed in the database, in "application" schema.

Since this migration, when i do a vaccumdb, i obtain an error :

vacuumdb: vacuuming of database "application" failed: ERROR:  function unaccent(text) does not exist

LINE 2: SELECT lower(unaccent($1));

                     ^

HINT:  No function matches the given name and argument types. You might need to add explicit type casts.

QUERY:

SELECT lower(unaccent($1));

CONTEXT:  SQL function "lower_unaccent" during inlining

VACUUM (VERBOSE, ANALYZE);

I removed and reinstalled the extension, but the error continue to appear.

Following this post : https://www.postgresql.org/message-id/CAPs%2BM8LCex6d%3DDeneofdsoJVijaG59m9V0ggbb3pOH7hZO4%2BcQ%40mail.gmail.com , i installed the extension in public schema, the message still appear.

If i do a vacuum in sql command, i haven't the error.

May you have an idea of the cause of this issue and how to resolve it?

Thank you

Greg