Hi Romane,
Thanks for the update and glad that the console error is fixed now.
To troubleshoot further around the date-picker field, I'll recommend the following steps:
1. Please temporarily disable all non-Toolset plugins and then check the date-picker field. If it gets fixed, you can start activating other plugins, one-by-one, to narrow down to a possible conflicting one.
2. You can also temporarily switch to a default WordPress theme like "Twenty Nineteen" and see if this issue is limited to the currently active "Toolset Starter" theme or any custom code in it.
Note: the "Toolset Starter" theme has been discontinued ( https://toolset.com/documentation/user-guides/toolset-starter-theme/ ) and is no longer under active development. It would be a good idea to permanently switch to a different theme that is still being updated and maintained - https://toolset.com/documentation/recommended-themes/
3. In case the issue still persists, I'll need a snapshot/clone of your website for further troubleshooting.
(it can be from this website or from another test website where the issue is reproducible)
We usually recommend the free Plugin “Duplicator” (http://wordpress.org/plugins/duplicator/) for this porpoise.
If you already know how Duplicator works, you can skip the instruction video and just send me the installer file and the zipped package you downloaded.
Duplicator Instructions:
hidden link
( note: I'll need both files and you'll probably want to use DropBox, Google Drive, or similar services, as the snapshot file will be quite big )
IMPORTANT: Remember to create or keep an admin account for me before creating the snapshot, or I won’t be able to log in. You may delete the new admin account once the snapshot has been built.
I will set your next answer as private so you can provide me with the information securely.
regards,
Waqar