I was actually just looking at that, since it seemed like a likely culprit to sort by last update, but display the publication date, and I think you may be right.
This came from a category view, but the output for one particular snag I hit is...
Code: Select all
+---------------------+---------------------+---------------------+
| updated | date_entered | date_updated |
+---------------------+---------------------+---------------------+
| 2014-03-23 18:55:03 | 2014-03-23 19:16:00 | 2014-03-25 08:09:11 |
| 2014-03-23 13:52:06 | 2014-03-23 21:16:00 | 2014-03-26 22:11:36 |
| 2014-03-23 19:16:31 | 2014-03-23 21:16:00 | 2014-03-26 00:38:40 |
+---------------------+---------------------+---------------------+
The times displayed (EDT) are 14:55, 9:52, and 15:16, so if I had to guess, the sort is based on date_entered, but we're seeing updated.
Edit: Failed to close a tag.