UserAgent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/68.0.3440.75 Safari/537.36

Steps to reproduce the problem:
(WARNING: example URL contains explicit sex content)

1. visit https://www.sexbarcelona.es/rosa

What is the expected behavior?
Should show the alert about an insecure connection, because the SSL certificate is invalid. Only by clicking "advanced" and "proceed at your own risk" (or whatever it's called), should one be allowed to browse the website, and even then, the "https" and the lock icon on the left of the address bar should be red and with a strike-through line

What went wrong?
It shows no warning, and it says "Secure" next to the address bar.

Try this from a command line:

p# wget https://www.sexbarcelona.es/rosa
--2018-08-13 18:20:03--  https://www.sexbarcelona.es/rosa
Resolving www.sexbarcelona.es (www.sexbarcelona.es)... 217.116.0.191
Connecting to www.sexbarcelona.es (www.sexbarcelona.es)|217.116.0.191|:443... connected.
ERROR: The certificate of `www.sexbarcelona.es' is not trusted.
ERROR: The certificate of `www.sexbarcelona.es' hasn't got a known issuer.

From another machine:
# wget https://www.sexbarcelona.es/rosa
wget: /usr/lib/libcrypto.so.0.9.8: no version information available (required by wget)
wget: /usr/lib/libssl.so.0.9.8: no version information available (required by wget)
--2018-08-13 18:18:37--  https://www.sexbarcelona.es/rosa
Resolving www.sexbarcelona.es... 217.116.0.191
Connecting to www.sexbarcelona.es|217.116.0.191|:443... connected.
ERROR: cannot verify www.sexbarcelona.es's certificate, issued by "/C=GB/ST=Bristol/L=Bristol/O=Basekit Ltd/OU=Certification Services/CN=*.invalid.domain/emailAddress=infrastructure@basekit.com":
  Self-signed certificate encountered.
ERROR: certificate common name "*.invalid.domain" doesn't match requested host name "www.sexbarcelona.es".
To connect to www.sexbarcelona.es insecurely, use '--no-check-certificate'.

Did this work before? N/A 

Chrome version: 68.0.3440.75  Channel: n/a
OS Version: 
Flash Version: 

Firefox considers that secure, too, but it seems pretty evident that both browsers are wrong.