Chrome Version: 64.0.3273.0 (Official Build) canary (64-bit)
OS: macOS 10.12.6

The following two fragments render differently with regards to the kerning between the counter character and the full stop:

<ol style="list-style: lower-greek inside; padding: 0; margin: 0;">
  <li style="padding: 0; margin: 0;"></li>
</ol>

and:

<p style="padding: 0; margin: 0;">α. </p>

Note this doesn't happen with all counter styles: it notably doesn't reproduce with decimal or decimal-leading-zero, and for some doesn't reproduce at 96dpi (though does at higher dpi).

As the early draft of Lists 3 says, "The contents of the ::marker are a text run containing the prefix of the <counter-style>, followed by the result of generating a counter representation for the <counter-style> and the value of the list-item counter on the originating element, followed by a text run containing the suffix of the <counter-style>".