bwauths need to explicitly request full consensuses when using tor 0.3.0 and later
Tor 0.3.0 merged #6769 (moved), which makes all tors use microdescriptors by default.
A side effect of this change was that FetchUselsssDescriptors 1 used to imply UseMicrodescriptors 0. Now it doesn't any more.
So bandwidth authorities need to set UseMicrodescriptors 0 in their torrcs, when using tor client versions 0.3.0 and later.
(Bandwidth authorities which use relays will continue to download full consensuses.)