Some of the blocked requests appear to be processed/sent twice

[AndriusA]

Description

Some network requests that get blocked appear processed and potentially resent twice among "Ads and Trackers Blocked" as well as in the Network tab in Dev Tools. Such duplicates do not appear in stable release (either counters, or network tab).

Steps to Reproduce

For stability, should be done via a web replay proxy, but can be reproduced with less dynamic sites

1. Visit a website in brave-dev, inspect number of things blocked. Good examples are qz.com or cnn.com
2. Visit same site on stable release, observe different count of things blocked
3. Copy over both lists to text editor, sort alphabetically to observe duplicates

Actual result:

visiting qz.com for example produces list:

https://api.keen.io/3.0/projects/5605844c46f9a7307bca48aa/events
https://atlanticmedia.122.2o7.net/b/ss/atlanticquartzproduction/1/H.24.4/s8994892886633?AQB=1&ndh=1&t=20%2F8%2F2018%2019%3A12%3A28%204%20-60&ce=UTF-8&ns=atlanticquartz&pageName=Home&g=https%3A%2F%2Fqz.com%2F&cc=USD&c3=Home&c4=%2F&c25=%7C&c26=desktop%20%7C%20landscape&c28=home&c44=work&s=3440x1440&c=24&j=1.6&v=N&k=Y&bw=1920&bh=1050&p=Chromium%20PDF%20Plugin%3BChromium%20PDF%20Viewer%3B&AQE=1
https://atlanticmedia.122.2o7.net/b/ss/atlanticquartzproduction/1/H.24.4/s8994892886633?AQB=1&ndh=1&t=20%2F8%2F2018%2019%3A12%3A28%204%20-60&ce=UTF-8&ns=atlanticquartz&pageName=Home&g=https%3A%2F%2Fqz.com%2F&cc=USD&c3=Home&c4=%2F&c25=%7C&c26=desktop%20%7C%20landscape&c28=home&c44=work&s=3440x1440&c=24&j=1.6&v=N&k=Y&bw=1920&bh=1050&p=Chromium%20PDF%20Plugin%3BChromium%20PDF%20Viewer%3B&AQE=1
https://tpc.googlesyndication.com/simgad/8879652923532983725
https://tpc.googlesyndication.com/simgad/8879652923532983725
https://www.googletagmanager.com/gtm.js?id=GTM-MRD738C
https://www.googletagservices.com/tag/js/gpt.js

Expected result:

On stable release the duplicates are not present.

Reproduces how often:

Easily reproduced, however best using a page replay proxy

Brave version (chrome://version info)

Brave	0.55.5 Chromium: 70.0.3538.16 (Official Build) dev (64-bit)
Revision	16ed95b41bb05e565b11fb66ac33c660b721f778-refs/branch-heads/3538@{#306}
OS	Mac OS X
JavaScript	V8 7.0.276.9
Flash	(Disabled)
User Agent	Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.16 Safari/537.36
Command Line	/Applications/Brave-Browser-Dev.app/Contents/MacOS/Brave Browser Dev --enable-tab-audio-muting --disable-domain-reliability --disable-chrome-google-url-tracking-client --no-pings --enable-features=EnableEmojiContextMenu,DesktopPWAWindowing,fill-on-account-select,NewExtensionUpdaterService --disable-features=SharedArrayBuffer --flag-switches-begin --flag-switches-end
Executable Path	/Applications/Brave-Browser-Dev.app/Contents/MacOS/Brave Browser Dev

Reproducible on current release:

No

Website problems only:

Disabling shields and observing requests received at the proxy, the duplicates are not present

[tildelowengrimm]

@srirambv could you check and see if this is fixed?

[tildelowengrimm]

@brave/legacy_qa — can you reproduce this?

[srirambv]

Will check and update results today