Problem is resolved. It wasn’t related to your plugin, but related to wp-config.php configs and HOST/SERVER urls as well as the wp_content setting in that config file.
I went through the suggested steps, none of them fixed the issue. All plugins deactivated. I even removed and reinstalled the Event Tickets plugins but the problem wasn’t solved.
I have so far tried to set the padding for the menu links to a minimum value to prevent them from wrapping around, but this doesn’t seem to be the answer.