Filters within filters

I just noticed that nesting pages will apply the external filter on top
of the internal one. For instance, I set up a page like so:

Part: body, Filter: markdown
<r:content part=“another_part” />

Part: another_part, Filter: none

The output is:

Is this desired? I would have hoped to have my unfiltered page part get
rendered, well, unfiltered. Thoughts anyone?