So this can be due to many reasons:
- User right clicks on the link and copies the link, then manually pastes it (not tracked on your site, but tracked at the destination)
- User opens the link in a new tab (right click and context menu, or center click, etc) (not tracked on your site, but tracked at the destination)
- User refreshes the destination, or navigates through the destination site then uses their "back" / browser history, and re-triggers that page tracking
- The destination URL was crawled by Google or another search engine, or posted on social media, etc (traffic would be going from third party sites to that destination outside of your flow)
- Users who are opted out of Adobe tracking / blocking Adobe tracking aren't being captured on your side, but are being captured on the destination by their code
If the discrepancy is really 50,000 to 10,000 I would say that URL is available outside of your site and that designation is getting traffic from other sources... that's too big a difference for the other options... or if that is an exaggeration, and the difference is noticeable but close, that will need to be an acceptable difference.. you cannot properly compare two different tracking systems and expect them to match....