Hi,

Try to add the following code snippet to the Custom CSS area in Theme Settings to fix this issue.

#billing_house_number_field,
#shipping_house_number_field{
	width: 47%;
    float: right;
}

#billing_house_number_suffix_field,
#shipping_house_number_suffix_field,
#billing_email_field {
	width: 100%;
}

And this part is for mobile devices

#billing_house_number_field,
#shipping_house_number_field{
	width: 100%;
    float: none;
}

Regards