Hi,
Data collection should still work for IE 11, I know Adobe stopped support the plugin for IE 11.
How Activity Map Works.
When the Activity Map module is loaded on the page it scans the DOM for any links on the page and gathers the following data.
These values are passed into a cookie when something is clicked, then sent once an image request is sent.
So if that cookie is being set while in IE 11 when the s.tl is clicked this cookie might not be cleared out in time or cleared out at all.
I would check the s_sq cookie to see if this is the case.
Thanks,
Steven Hofheins | Adobe Support