No pings are sent from a Normal Window if a Private one is opened right after the experiment is installed

[Softvision-CristinaBadescu]

[Affected versions]:

• Firefox 61.0.1

[Affected Platforms]:

• All Windows
• All Mac
• All Linux

[Prerequisites]:

• You can download the latest version of the "TAAR v3" add-on from here:https://bugzilla.mozilla.org/show_bug.cgi?id=1469546.
• Create the following prefs in the "about:config" page: "shieldStudy.logLevel" as string and set it to "All"; "extensions.taarexpv3_shield_mozilla_org.test.variationName" as string and set it to "control", "intervention-a" or "intervention-b"

[Steps to reproduce]:

1. Open the Firefox browser with the profile from prerequisites.
2. Install the TAAR add-on from Bug 1469546 and open a Private Window.
3. Switch back to the Normal Window and navigate to a website (https://www.wikipedia.org/).
4. Click 3 different links (one after another) from the website's content (without leaving the current active tab).
5. Navigate to the "about:telemetry" page and select the "Archived ping data" ("shield-study-addon" ping type).
6. Click the "Raw JSON" button.
7. Observe the last sent ping.

[Expected result]:

• The doorhanger trigger ping is displayed.

[Actual results]:

• The installation trigger ping is displayed.

[Notes]:

• Also, the add-ons installation pings are not sent. You don't need to follow the steps above, it's only necessary to have a Private Window opened and anytime you install add-ons from the Normal one, the pings are not sent.
• This issue is also reproducible on TAAR 3.0.1.
• Here is a screen recording with the issue:

[motin]

Closing this since it is expected behavior, documented under "Peculiarities" in https://github.com/motin/taar-experiment-v3-shield-study/blob/develop/docs/TESTPLAN.md#peculiarities Ping @mlopatka fyi