Not all http connections reported


I noticed that some of my agents do not register all requests performed by a web browser. I cannot figure out what it is caused by but on attached waterfall chart you can see that while content is being downloaded (green line on bandwidth chart at the bottom), no connections are visible but gaps.

I noticed it only for one web application so far. Does anyone have the same problem? I run 217 wptdriver version on windows 7

What is more, there is an inconsistency between for example total bytes transferred and what can be seen in request details

Update: it occurs also on some agents running IE9 :-/

Also on Windows 7.

What is important it does not correlate with this problem:

and it is observable only with wptdriver. urlblast running IE9 reports all http requests

I managed to reproduce it on public instance.
Bad behavior:
Good as a reference: