Known issue

Problem:
The client was experiencing an issue with the event calendar on the French version of their site, where the calendar would get stuck in a loop when performing actions such as queries, searches, or date changes. This was suspected to be due to WPML translating a URL for a script incorrectly, causing JavaScript errors in the console.
Solution:
We suggested that the issue might be related to a known problem with The Events Calendar and custom slug translations, similar to what is described in https://wpml.org/errata/the-events-calendar-incorrect-link-format-with-custom-slug-translations/. We recommended trying the workaround mentioned there. Additionally, upon further inspection, it was found that remnants of a previous translation app in the .htaccess file were causing the issue. Removing these remnants resolved the problem.

If this solution does not apply to your case, or if it seems outdated, we highly recommend checking related known issues at https://wpml.org/known-issues/, verifying the version of the permanent fix, and confirming that you have installed the latest versions of themes and plugins. If issues persist, please open a new support ticket.