Google Search Console Mobile-Usability VS Index Coverage

[Beetle]

I have just logged into my Google Search Console and noticed that although Google has indicated that I have 394 valid urls submitted and indexed (Index --> Coverage), the mobile usability only shows 294 valid urls (0 errors).

Does anyone know what might be causing this? And if it is an issue?

Side Note: The website is very fast so I don't think it is a speed issue.

Thanks in advance for your input.

 

[Ryuzaki]

@Beetle, it could be that your site isn't 100% migrated over to the mobile-first index. As of March 5th, 2020, only 70% of sites were migrated over. They said they'd have them all done by September 2020, but we all know how those predictions go.

It could also be the case that some of your pages haven't had enough traffic to collect enough data from actual users using the Chrome Lighthouse data that reports back to Google. I'm not sure if they use user data or run the test on every page in Search Console, but that could be another reason why the total numbers don't match.

I wouldn't worry about it. I've rarely seen numbers match in Search Console vs. Search Console, Analytics vs. Analytics, or Console vs. Analytics. There's always discrepancies for whatever reason.