Submission redirection not working with mobile theme

My WordPress site uses 2 different themes: 1 for Desktop and 1 for Mobile.
Using the “ip_on_sent_ok” property in (for example “ip_on_sent_ok:http://www.mywebsite.it/thank-you-page“) works fine for desktop theme. The redirection is done and the page http://www.mywebsite.it/thank-you-page is displayed. If I access the form from mobile, the redirection do not took place… the form is sent but the in-page default message is displayed.

Is there any check I could do to figure out why this happens?

Thank you

https://wordpress.org/plugins/contact-form-7/