That's because of SNI, anytime you install an SSL on a domain that resides on a shared IP any domain that does NOT contain an SSL will automatically default to the first virtualhost in the Apache conf that DOES have an SSL.
You would want to either install SSL's on ALL domains, or what you can do is install your server hostnames SSL and then set that SSL as the Primary SSL.
Steps are:
-WHM > Service Configuration » Manage Service SSL Certificates
Click "Apply Certificate to Another Service" on any of the services, the boxes will prefill. Copy the first box "Certificate".
-Then go to WHM > SSL/TLS » Install an SSL Certificate on a Domain
Copy / paste the certificate into the Certificate box and click "Autofill by Certificate", all boxes will prefill.
In the "IP Address" box make sure to fill in the shared IP of the reseller.
Click Install.
-Finally, go to WHM > SSL/TLS » Manage SSL Hosts
Search for your server hostname, there may be more than one so find the one that is tied to the IP in question. To the far right column, click "Make Primary".
Now anytime you visit any domain over HTTPS(that does not contain an SSL) or
https://IP you will be directed to the default cPanel page.