Zammad on UCS with Letsencrypt

Maybe this is related to a problem we had with the joinscript (/usr/lib/univention-install/50zammad.inst). Zammad never becomes ready because this loop does not end:

# Check readiness of Zammad-Docker
ZAMMAD_MAIL_SIZE="10"
while [ ! $ZAMMAD_SRUN ]; do
  sleep 2
  ZAMMAD_MAIL_SIZE="$(docker exec -i "$ZAMMAD_CONTAINER" rails r "p Setting.get('postmaster_max_size')")"
  ZAMMAD_MAIL_SIZE="$(echo $ZAMMAD_MAIL_SIZE| bc)"
  echo "# ... Checking Zammad-Mail-Size: "$ZAMMAD_MAIL_SIZE" MB                         #"

  if [ $ZAMMAD_MAIL_SIZE -eq "35" ]; then
    ZAMMAD_SRUN=false
  fi
done

When running

docker exec -i zammad_zammad-railsserver_1 rails r "p Setting.get('postmaster_max_size')"                                                                                        

it returns more than just the 35:

I, [2019-09-26T12:24:58.288014 #25-47115586047840]  INFO -- : Setting.set('product_logo', "6d5d035a808e2d90c76822c304ea6d23.png")
"35"