Issues with timestamps not being displayed properly

Hey there! o/

I’m absolutely loving Vapid so far. While tinkering around with all the possibilities I ran into a little issue with the timestamps tho. Since I couldn’t find any relevant topics on the forum or open issues on GitHub I thought I’d just try my luck asking for help.
I’ve built a little blog for testing purposes. I want to display metainformation for every post but instead of properly rendering timestamps I just get the plain tag printed out.

Markup: <div>Published: {{ _created_at format="%m/%d/%Y" }}</div>
Result: Published: {{posts::_created_at}}

This is straightup copied from the documentation yet it doesn’t seem to yield the result that I’d like see. Am I missing something important? The version of Node I’m running is v14.2.0 in case that’s relevant. c:

Best regards
~