`brz diff --using X --diff-options Y` not working

I'm trying Breezy for the first time, version
3.2.2 installed with `pip3` in Debian 10.12.

I want to use some external diff tools (mainly Neovim), but I'm having
problems:

  brz diff --using sdiff --diff-options -s
  brz diff --using=sdiff --diff-options=-s
  brz diff --using=sdiff --diff-options="-s"

I always get this error:

  sdiff: extra operand 's'

When I try the long option instead:

  brz diff --using=sdiff --diff-options=--suppress-common-lines
  brz diff --using=sdiff --diff-options="--suppress-common-lines"

then the error is the following:

  sdiff: extra operand '-'

When I try Neovim or Vim:

  brz diff --using /usr/local/bin/nvim --diff-option -dR

then nothing happens, except the command line freezes until I hit
Ctrl-C.

I've defined also some alias in <~/.config/breezy/breezy.conf>:

  [ALIASES]
  ndiff = "diff --using /usr/local/bin/nvim --diff-option -dR"
  vdiff = "diff --using /usr/local/bin/vim --diff-option -dR"
  sdiff = "diff --using /usr/bin/sdiff --diff-option -Bs"
  ddiff = "diff --using /usr/bin/diff --diff-option -Bs"

but they make no difference: they cause the same errors.

It seems a bug, because also the following example from `brz help diff`
fails:

  brz diff --using /usr/bin/diff --diff-options -wu
  diff: extra operand 'w'