Assume that the WinHTTP Web Proxy Auto-Discovery Service is disabled in your environment. Additionally, the Automatically detect settings check box is selected in the Local Area Network (LAN) settings of Internet Explorer 10 or Internet Explorer 11 on your computer. In this situation, any proxy routing script (such as the wpad.dat file) that is discovered may be downloaded. However, the script file is discarded before it can be reused for additional navigation requests. Therefore, it may cause a bandwidth issue to download the script file again for new navigation requests.
To resolve this issue, install the most recent cumulative security update for Internet Explorer. To do this, go to Microsoft Update. Additionally, see the technical information about the most recent cumulative security update for Internet Explorer.
This update was first included in the April 2015 cumulative security update for Internet Explorer (MS15-032).
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
See the terminology that Microsoft uses to describe software updates.