Translation keeps changing

Hi there,

I want to change the (Dutch) word “Evenementen” to “Cursussen”. (Events to courses). For that i have changed all words in the PO file and regenerated a new MO file as instructed on this page: https://theeventscalendar.com/knowledgebase/k/how-to-override-plugin-language-files/

I’ve uploaded the new MO en PO files, with the same name, the the language folder in the wordpress plugins folder.

This works for a couple of hours and then it reverts back to the “standard” dutch translation. When, after uploading the custom files, I go to the wordpress update page it states that new translation files are found. After pressing that, it also changes back to the “standard” dutch version.

What am i doing wrong here?

I have one additional plugin for the events calendar and that is this one: https://www.ads-software.com/plugins/registrations-for-the-events-calendar/