[Desktop] AC list not as expected after watching YT video (high youtube % in comparison to video length)

[LaurenWags]

Description

Sometimes after watching a YT video the AC list is not as expected. This is an intermittent issue, I can't reproduce 100% but below are the two scenarios where I've seen AC not being populated as expected

Steps to Reproduce

Scenario 2:

1. Clean profile, enable Rewards
2. Open a new tab and go to youtube.com
3. Search for "snl"
4. In the search results click on Saturday Night Live (it's probably the first result, you want the channel's page, not an individual video)
5. After https://www.youtube.com/user/SaturdayNightLive loads, let the short (15s) video on this page finish playing.
6. Open the panel or brave://rewards --> youtube.com has a big % (like 75ish percent) and the video itself is the rest (~25%)

Reproduces how often:

intermittent, I have seen the above a few times, but can't solidly reproduce. Maybe happens ~10-20% of the time

Brave version (brave://version info)

Brave | 1.16.46 Chromium: 86.0.4240.55 (Official Build) nightly (x86_64)
-- | --
Revision | a6d625ef6f7fe8ea0675f1cf759155a05ee1be40-refs/branch-heads/4240@{#953}
OS | macOS Version 10.14.6 (Build 18G3020)

Version/Channel Information:

• Can you reproduce this issue with the current release? could not reproduce with 1.14.x
• Can you reproduce this issue with the beta channel? could not reproduce with 1.15.x
• Can you reproduce this issue with the nightly channel? only intermittently reproduced with 1.16.x

Other Additional Information:

• Does the issue resolve itself when disabling Brave Shields?
• Does the issue resolve itself when disabling Brave Rewards?
• Is the issue reproducible on the latest version of Chrome?

Miscellaneous Information:

cc @NejcZdovc @emerick

[LaurenWags]

Could be related to right clicking on a link and opening the video in a new tab. (this was logged as its own issue - https://github.com/brave/brave-browser/issues/11933)