BridgeDistribution in torrc is being ignored

Even though specifying HTTPS as BridgeDistribution in torrc:

$ grep BridgeDistribution /etc/tor/torrc
BridgeDistribution https

...it appears as if rdsys overrides or ignores this:

29e1f1ffbc4f4b306f3e3ffb52f58757620ea34c settings transport=obfs4 ip=4 blocklist=ru

Is this intended? If yes, why, and where is it documented?