Hi think the error is due on that IE11 user-agent will return to be:
Mozilla/5.0 (Windows NT 10.0; WOW64; Trident/7.0; rv:11.0) like Gecko
compare to prior when you can check for MSIE string:
Mozilla/5.0 (compatible; MSIE 10.0; Windows NT 6.1; WOW64; Trident/6.0)
as CA use it to determine the way to construct the windows it may return false to isIE and the window is construct for other brwsoer causing ie11 to not react as expected.
CA did update the code for IE11 but apparently didn't manage all the case so I will suggest you to open a case with support.
Workaround is to fine the corresponding in the std_head.js and add your own case there like example below for the size of the window:
var winHeight = ( _browser.isIE ? root.offsetHeight
To
var winHeight = ( _browser.isIE11 ? root.offsetHeight
Hope this help.
/J