Hello @fideliza,
As far as we have checked this theme locally and it works all fine and all the slider settings are working perfectly.
However the slider functionality is not checked with any third party plugins.
So, if you have installed any third party plugins then please try disabling them one by one and check you site if the issue is fixed. If the issue is fixed you will know the exact plugin that have created the issue.
But if the issue still continues then kindly let us know.
Thank you .
Best Regards!!