Not possible to disable DoNoTrack Header in Tor Browser during non-Tor usage

When TorLauncher is disabled in Tor Browser (to enable bypass of the Tor network), it is no longer possible to control DoNotTrack Header in about:preferences#privacy. DNT Header is always enabled when checking for example on panopticlick.eff.org in spite of setting DoNotTrack to disabled in about:preferences or setting privacy.donottrackheader.enabled to false in about:config.

Disabling or enabling TorButton have no effect on this issue.

This bug seems new in TB version 7.5.4, even though I am not completely sure.

Trac:
Username: loxia_01