looks like you call context:SetColor() somewhere in your script.
As a quick workaround you can call context:SetColor(1,1,1,1) right before context:DrawImage() in the Note.lua file in the PostRender function.
//Edit: I just added the setcolor for the texture drawing and also added some more text settings like text alignment, size and line spacing.
I just uploaded it to the steam workshop (first item i uploaded to the workshop) http://steamcommunity.com/sharedfiles/filedetails/?id=388493460