Affected versions

• Firefox 72.0.2
• Firefox 73.0b11
• Firefox 74.0a1

Affected platforms

• Windows 10 & 7
• macOS 10.15
• Ubuntu 18.04

Steps to reproduce

1. Launch Firefox
2. Access this link
3. Now access this link in the same tab.
4. Go back to the previous page

Expected result

• The tracking protection shield is active and blocking

Actual result

• The tracking protection shield is inactive and "No trackers known to Firefox/Nightly were detected on this page" message is shown

Regression range
I will see for a regression

Additional notes

• The issue can be seen in the attachment.
• By doing the steps and refreshing the page after, the tracking protection will be active again.

Regression range

• Last good build_date: 2018-10-23
• First bad build_date: 2018-10-24
• Pushlog URL

The range is just for the specified steps.
Builds that are considered "Good" still have an issue, as in the initial load of the page show "No trackers known" no matter of the other steps; so can only assume that this is a edge-case scenario that might have not been covered.
In regards to this, removing the regression keyword; feel free to add it back if information comes up to disprove the finding.

The priority flag is not set for this bug.
:ewright, could you have a look please?

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