Batched mode causes bug in cli/script export

This is my bug_script.lua:

do

  local spr = app.activeSprite

  if not spr then return app.alert "There is no active sprite" end

  app.transaction(

     function()

     app.activeLayer.name = "outline"

     app.command.DuplicateLayer()

     app.activeLayer.name = "blur"

     app.command.DuplicateLayer()

     app.activeLayer.name = "original"

     app.command.GotoPreviousLayer()

     app.command.ConvolutionMatrix {

        ui=false,

        channels=FilterChannels.RGBA,

        tiledMode=none,

        fromResource="blur-3x3"

     }

     app.command.GotoPreviousLayer()

     app.command.Outline {

        ui=false,

        channels=FilterChannels.ALPHA,

        place='outside',

        matrix='circle',

        color=Color{ r=0, g=0, b=0 },

        bgColor=Color(),

        tiledMode='none'

     }

     app.command.FlattenLayers()

  end)

end

When I execute this script with
Aseprite.exe test.png --script bug_script.lua --save-as bug_output.png
I get a prompt, and the save results in a correct result (a faintly colored outline). However add a -b and the result is wrong (something wrong with alpha values, not quite sure)
Version is 1.2.16