[TYPO3-mvc] Extension "news". <f:format.date> gives unexpected output

[Enrique Moreno]

I have 2 servers, which are (in theory) synchronized. I have a template for the extension "news" with the following code:

    <f:format.date format="%A">{newsItem.datetime}</f:format.date>

In the dev server, the output is "Friday", which is the expected output.

But in the Live Server, the output is "%AM"

Why am i having this difference between both servers? How could I set it right?