When upgrading to 1.5, my wp-rss2.php seems to be producing the wrong timestamp / zone combinations. The posts in the blog are fine, just when looked at through the feed they are wrong. I think the problem is on line 36 of the wp-rss2.php file:
<pubDate><?php echo mysql2date('D, d M Y H:i:s +0000', get_the_time('Y-m-d H:i:s')); ?></pubDate>
The timezone +0000 is hardcoded but the get_the_time function is pulling back a local timestamp. Either the timezone needs to be pulled from the database or the get_the_time function needs to pull GMT times. Changing +0000 to my timezone fixes it ... but is this really a bug or do I have another upgrade issue?