"Headers already sent" error on "view previous orders" page

I have a site running Jigoshop (Version 1.12.1) and am getting a “headers already sent” error on just one page, the “view order” page. This happens even when I switch to twentyfourteen with all plugins except jigoshop disabled.

Here is the error that displays on the page in place of where the content should be:
Warning: Cannot modify header information – headers already sent by (output started at /home/[full server path hidden]/wp-includes/functions.php:3318) in /home/[full server path hidden]/wp-includes/pluggable.php on line 1173

And when debug is set to true, here is the warning I see…

Warning: session_start() [function.session-start]: Cannot send session cache limiter – headers already sent (output started at /home/[full server path hidden]/wp-includes/functions.php:3318) in/home/[full server path hidden]/wp-content/plugins/jigoshop/classes/jigoshop_session.class.php on line 22

I have googled and found nothing. This is a dev site with just one user so I can’t tell if it’s because I’m an admin with no previous orders, or if it’s a real problem that will be on the live site. Can anyone help?!

https://www.ads-software.com/plugins/jigoshop/