@firedclyde
Your server / optimization / configuration is unable to keep pace with the amount of pageviews and the ads are probably loading past the user eyeballs or just not fast enough. Just put a unit in ATF on first load on internal pages, this unit is killing it again after so many years for me its not even funny.
I have a few points about this statement.
1- You can easily check ad viewability, go to reports and check "Active View Viewable" this metric measure the percentage of impressions that are considered viewable. If what you describe above is occurring then you should see negative correlation between AVV and page views. I don't see any correlation. Where I do see correlation, positive correlation, is between page RPM and AVV.
2- "Your server" has no direct impact on the performance of AdSense's ad units. Typically the issue is that "your server" is fast to load the page, but the ads lag far behind. The end result would still be as you describe.
3- The only real fix to this, if it is in fact a problem, is to place ad units in close proximity to the most engaging content on your page. Like this the user will begin to engage with your content as the ad loads, once is loaded the ad will appear in the view or very close to the view.
Studies published by AdSense showed that banner ads ATF on mobile perform less well than ads placed at or slightly below the fold. This is because as a page loads on mobile typically the first thing the user sees is a menu and a title, so they immediately begin scrolling, thus scrolling by the ads before they are loaded. Moving the ad further down, gives the ad a few miliseconds more to load and is likely placed closer to the engaging content.
In my experience focusing on AVV is important. It is a big driver revnue (RPM). A user can't click on an ad if they can't see it.
@abu009
If we set our site to load ads first and then content
Loading of ads does not count towards your page speed. Ads are intentionally loaded asynchronously in order for them not to impede the loading of the content. You can force the ads to load synchronously, in other words blocking content loading until the ad has been fully loaded and rendered. But doing this will cause significant delays to your page speed. Since page speed is a ranking factor the impact of such a strategy could be devastating in terms of search performance. Not to mention, that if content is slow to load, the user will bounce in much higher numbers which in turn can compound the impact on search performance. See my suggestions above it is a far more effective strategy.