Email headers not being appended in transaction summary emails

I've noticed that on every cron run a few errors are being thrown up by common.inc
This only occurs when there are transaction summaries to be sent.
The summaries that arrive do not have the email headers that are set in the store.module on line 150 because they are not in the form of an array as expected by drupa_mail

This has the effect of setting the "from" address to the PHP / Server default, instead of the Drupal site email.

The problems are minor. The emails still arrive and generally are not responded to so the from address is not important.

Here's the change I made in order to get it working correctly

Comment out the original line
// $headers = "From: $from\nReply-to: $from\nX-Mailer: PHP\nReturn-path: $from\nErrors-to: $from";

And then add this

$headers = array(
"From"=>"$from",
"Reply-to"=>"$from",
"X-Mailer"=>"PHP",
"Return-path"=>"$from",
"Errors-to"=>"$from");