What is the custom format string you are using in the latest events module?

Also if you give us the URL we can when in case its caused by CSS

The link is here:
https://otvbornholm.dk/

I use this as custom format:

<span class="icon-calendar"></span>${startDate(%A %d. %B %Y)}

<span class="icon-time"></span>${startDate(%k:%M)}

<span class="icon-hand-right"></span>${title}

I suspect its from the language settings in PHP

You can work around id by adding this custom CSS to your JEvents custom css file - make sure the module is configured to load it

.mod_events_latest_date {

  text-transform: capitalize;

}