How do I fix the “Pageview event mismatch” warning on my Google tag?

A pageview mismatch warning occurs when different pages on your domain fire your Google tag with conflicting container IDs, or when structural routing scripts send incorrect URL parameters back to Google.

“This is usually a container ID conflict between pages, or a routing script quietly passing the wrong URL back to Google. I’ll track down the mismatch and fix it within 24 hours for $99.”
— Jeff Bollettino, Managing Director, Ignite Conversions