How to get the sample transform type to work?

[V3XATI0N]

I have the following sample:

      dd_log_tags:
        type: sample
        inputs:
          - dd_log_tags_pre
        group_by: "{{ service }}"
        ratio: 0.1
        exclude: '.aggregator == "datadog"'

But this does not actually apply a sample ratio, I am still getting 100% of tags from the dd_log_tags_pre transform (which works fine). Every single event has an aggregator key, and some of those keys are datadog. I just want to take everything that isn't set to datadog and decrease it by 90% per service. As far as I can tell from the docs, this is correct, but it does nothing.