Hello, that's unusual. Can you try the following troubleshooting steps first?
- Please update your Toolset plugins to the latest versions.
- Temporarily deactivate all plugins except Types and Views, and activate a default theme like Twenty Twenty.
- If you have any custom code in wp-admin > Toolset > Settings > Custom code, please temporarily deactivate it.
- Place the custom field shortcode directly in the Event post content:
[types field="dataevento" style="text" format="l j F Y" id=""][/types]
- If a Content Template is assigned to this post, disconnect it temporarily.
- Check the post on the front-end. Is the date displayed correctly? If so, reactivate your theme and other plugins one by one until the problem returns.
- Tell me your settings in wp-admin > Settings > General for Timezone, Date format and Time format.