TestComplete (Web module) .keys() method in IE11 missing some letters

I have an issue with TestComplete 10.6 and IE11. While typing text to a textarea IE11 is missing some letters.

Simple example of the test:

function Test1()
{
var textarea; Browsers.Item(btIexplorer).Navigate("http://www.w3schools.com/tags/tryit.asp?filename=tryhtml_textarea");

textarea = Aliases.browser.pageWwwW3schoolsComTagsTryitAspF.frameIframeresult.textarea;

textarea.Click(264, 54);
textarea.Keys("[Enter]the quick brown fox jumps over the lazy dog");
textarea.Keys("[Enter]the quick brown fox jumps over the lazy dog");
}

The result is randomly missed letters. E.g.:

the quick brown fox jumps over thlazy dg
the quick brown fox jmps over the lazy dog

 

TestComplete Key pressing delay,ms = 250

I checked it on two different VMs and they produce the same issue. I do follow the Smartbears IE documentation to prepare the browser before testing.

Please let me know if you get the same results or that's something relating to my TestComplete configuration.