Hey Werner,
I’ve tested this on my local install using the Event Calendar and Event List widget but wasn’t able to replicate the issue and the times there respected the WP format.
I would suggest following the Testing for Conflicts procedures here to see if there is a conflict with another plugin or theme. I would also be happy to review your System Information to see if there is something there that might be causing an issue and could be associated with something we could address.
However, to properly set expectations here, I’m limited here to helping to see if there is a bug in our plugin that we can address. I’m not able to provide support for this particular issue and helping to resolve it here in our Translations forum. If you have an account here, I would welcome you to open a thread in one of our premium forums for additional support.
Thanks!