Contact Search Results Address Type
MikeLab, Welcome to CiviCRM SE. 

The address to be displayed on search result (primary or non-primary) is based on the setting 'Search Primary Details Only'.

You can change the value of this setting by navigating to CiviCRM >> Administrator >> Customize Data and Screens >> Search Preferences. 

If you set 'Search Primary Details Only' to yes then it search address or phone or email on primary, if no then it will search on all address or phone or email. The same logic also works on listing.

HTH

Pradeep