Howdy Rene,
Welcome to our support forums and thanks for reaching out to us. I’ll help you out with this issue!
I’ve tested this myself and it’s indeed failing π Unfortunately everything indicates this is a bug in our code.
You can downgrade the plugins to version 3.12.6 where I could confirm this is not happening or alternatively patch a plugin file until this fix is included (most probably) in the upcoming maintenance release.
If you are down with patching the core file (which is something we do not usually encourage users to do), just replace the content of the file ‘wp-content/plugins/events-calendar-pro/src/Tribe/CountDown_Widget.php’ with the content of this gist:
https://gist.github.com/niconerd/d3dfe20c9ccaa5c80ef0
That should fix this issue until the maintenance release is out,
Please let me know if it works as expected,
Best,
Nico