UEM fundementals are still unclear with this example. Could someone lend insight.

I thought I was clear with the fundementals of UEM but the following problem says I am not.  I am hoping someone can lend insight.   I have UEM implemented on an appserver.  The insertion is not happening for all pages except 1 page.  That page is generated when a person is at a "date" field and clicks the calendar icon.  The calendar page pops up.  If I view source, the dtagent is inserted.  The first sign of a visit is only when the calendar icon is clicked. Clicks of only calendar activity are the only actions that are captured.  

I am told that all pages (except the calendar page) are dynamically created and put together on the app server before being sent to the webserver.  I am also told that the calendar page is a jsp page that lives on the web server.  With UEM on the app server, how is it missing insertion on everything that is put together on the app server, but is able to captured   that which is created on the webserver.

I have checked that all HTML syntax is correct and have had a Dynatrace consultant verify that it is correct.   I have gone through every bullet of the documentation on why insertions would not take place.  I have also changed the placement of the insertion as the document suggests.  

The fact that insertion is taking place on the one page says that configuration is correct I would think.  I might consider putting UEM on the web server but our web server licenses are limited so I would need to understand why that would be appropriate because with the page being put together on the app server, I would think having UEM on the app server should work.

Does anyone have any thoughts that can help me think through this?

Thanks,

David