rspamd: cannot load redis server from obj

Hi,
we are trying to setup various rate limits via rspamd config `/etc/rspamd/local.d/ratelimit.conf`, but when we execute `rspamadm configtest` to check that everything is ok we receive a series of errors like:

Code:

[...]
cannot load redis server from obj: {[rates] = {[smtp_mail_daily_limit] = {[selector] = user.lower, [bucket] = {[1] = {[rate] = 300 / 24h, [burst] = 300}}}}, [whitelisted_rcpts] = postmaster,mailer-daemon}, processed to {[timeout] = 1, [expand_keys] = false, [read_only] = true}
[...]
syntax OK

a similar error appears for other modules.
Have we messed up something related to redis? Or is it something else?
We allready tried to clean the redis DB with no apparent difference, and the problem persists emptying the `local.d/ratelimit.conf` file

This server is running debian11, redis 6.0.16, rspamd 3.2 (but the same issue appears on a newer version like 3.6)
The config we tried to deploy:

Code:

rates {
        smtp_mail_daily_limit = {
          #
          # Default SMTP 300 mail / 24h for authenticated user
          #
          selector = 'user.lower';
          bucket = [
          {
                burst = 300;
                rate = "300 / 24h";
          }]
        }
        web_mail_daily_limit = {
          #
          # Default 20 mail / 24h for NOT authenticated user
          #
          selector = 'digest(header("Subject");header("From"))';
          bucket = [
          {
                burst = 20;
                rate = "20 / 24h";
          }]
        }
}