Why Do Clicks Not Match in Ui.Marketing Dashboard and Google Analytics?

This article discusses why clicks seen within the Ui.Marketing reporting dashboard may not align with what you're seeing in Google Analytics

The data pulled into Google Analytics is based on site interaction. The TradeDesk data/ad serving is based on and tracked by ad server actions. These are two different things and should not be compared the way in which they are (both data sets are not apples to apples). Although we may see similar trends/data, these tools track these events differently. A click will never be 1:1 with a session.

Also, if the average time on site is less than 1 second (if the user bounces off the site before the pixel or other parts of the site load), it will not get counted on our end.

This article further describes how Google Analytics attributes sessions, which again is much different from our DSP. https://support.google.com/analytics/answer/2731565