This occurs even when "Run in Private Windows" is set to "Don't Allow" and it stops occurring when the extension is disabled completely and a new private session is begun.
Taken from the second bug I linked from "ale.carrazzoni":
Steps to reproduce:
I download a file in private mode. Then I change to another tab or close the tab.
Actual results:
The downloads icon dissapears. When I check the download list, the download is gone, as if I never downloaded anything in the first place (that is, it doesn't appear as cancelled or failed).
Probably related to this bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1188732 And possibly this one: https://bugzilla.mozilla.org/show_bug.cgi?id=1474743
This occurs even when "Run in Private Windows" is set to "Don't Allow" and it stops occurring when the extension is disabled completely and a new private session is begun.
Taken from the second bug I linked from "ale.carrazzoni":