Thanks for the suggestion. I will write to the developer of JigoShop (possibly post in that forum) about this conflict.
Funny thing is that the code for <strong>add_filter('wp_mail_from', ...)</strong> is already commented, but the one for add_filter('wp_mail_from_name', ...) is not commented out.
Maybe it got left behind as an artifact. Either way, I will communicate with JigoShop development team.