The SharePoint farm was built on port 80 and extended to 443. 80 is currently in the default zone with 443 in the extranet zone. I have Search crawling both zones, but when a user performs a search on the extranet zone, they get "Object reference not set to an instance of an object." If I perform a search on port 80, I get no errors.
The zones use different authentication methods, and I am not seeing any errors with the search crawl.