The server logs contain entries like the following:
2023-09-13 04:47:48.698 UTC  ERROR: canceling autovacuum task 2023-09-13 04:47:48.698 UTC  CONTEXT: while cleaning up index "idx_user_ssh_authorized_keys_username" of relation "public.user_ssh_authorized_keys"
is this a problem?
In general no, it is expected to happen. Basically what that error message means is that when Postgres was doing its automatic background table cleanup tasks, a query came in that couldn't run with the cleanup task concurrently, so Postgres canceled cleaning up to let the query run. Unfortunately Postgres logs it at an "error" level instead of an "info" or other less severe level.