Hey Alan,
first of all, thank you for the purchase!
I will go over the questions in the same order:
1). It is indeed a bug, please accept my apologies and thank you for reporting! Please download this archive, unzip it, and upload into the theme folder (/wp-content/themes/Kanso/), replacing the existing files.
2). Could you please clarify – did you upload the image via the “Website background: image” field in the “Page Elements” tab of the Theme Options panel?
Sincerely,
Andrii / Satori Studio