I recently downloaded QGIS 2.16.0-Nødebo and noticed the ascending/descending ordering of the attribute table has changed (tested with integer, integer64, real and string type fields). Couldn't find a bug report for this so thought I would ask here if anyone has experienced this before I add a report?
I can confirm the issue in 2.16.1 and the current development version. Here's the ticket https://hub.qgis.org/issues/15366
It's fixed now and will be in the upcoming releases: https://github.com/qgis/QGIS/commit/ea0f4da58c87bc590f8b23049da0963ee9d9cd23