Dialog canvas problem with transparent sprites (gc:drawImage)

Bug Reports
1

Hello
I’m sure there’s a bug with draw:image. When I draw any transparent color in my sprite, I get a weird effect.

01
011920×1080 117 KB

Additionally, if I fill the sprite with any color with 0 alpha, the effect appears! (Only white color with 0 alpha has no side effect).

02
021920×1080 188 KB

local sprite = app.activeSprite
if not sprite then return end

local dlg = Dialog { title = "Dialog Canvas" }
dlg:canvas {
    width = 128,
    height = 128,
    hexpand = true,
    vexpand = true,
    autoscaling=true,
    onpaint = function(ev)
        local gc = ev.context
        local spriteImage = Image(sprite.width, sprite.height )
        spriteImage:drawSprite(sprite, app.frame )

        local srcRect = Rectangle(0, 0, 32, 32)
        local distRect = Rectangle(0, 0, 128, 128)

        gc.color = Color {r = 255, g = 255, b = 255, a = 255}
        gc:fillRect(distRect)

        gc:drawImage(spriteImage, srcRect, distRect)            
    end
}

dlg:show { wait = false }

I’ve looked into this topic, but there doesn’t seem to be a definitive solution for drawing in transparent mode. He just removes image transparency by redrawing.
I tested my code on Aseprite 1.3.2 and 1.35
Thank you.