Squid ssl_error_bad_cert_domain for non html requests

[tobiascapin]

I installed squid with ssl_bump, all my clients trusts pfsense as a CA and now certificates from pfsense are trusted.

I got some problem with some websites where main html page has a certificate and its resources (css, js…) are linked to another hostname with another certificate. The page is simple loaded as plain html without that resource due to certificate problem of resources.

This is my configuration.

And this is a failur case:
https://wizzair.com/it-IT/Search

The main html page is correctly loaded and the certificate is accepted.

If I try to load one of the resource url, for example:
https://cdn.static.wizzair.com/static/bundle_versioned_Release-patch_20150410.1/styles.css

I got the problem:
ssl_error_bad_cert_domain

This is the certifiate issue from squid (and trusted from the client except for the CN mismatch):

As you can see, the CN of the certificate is a ip address and not the hostname cdn.static.wizzair.com.
Why this behavour? What is that ip address? Why squid doesn't use the right hotname to issue its certificate to client?

I thought that would be a SAN prolema, so I checked the original certificate and this is issue with CN=cdn.static.wizzair.com so this is not and alternative name problem.

Thank you.