Ardour has been updated to v2.8.2. This update contains a fix for a another critical bug on OS X that causes ardour to crash when deleting plug-ins with Carbon-based user interfaces. There are also two other small fixes - logarithmic plugin parameters can now be modified sensibly, and when importing files using the "copy files to session" option, an existing BWF timestamp is no longer lost.
All OS X users are recommended to upgrade immediately - for those who have paid for any previous 2.8-series version, it is a free upgrade. Linux users may choose to wait for 2.8.3 in a couple of weeks which will contain a dozen or so other bug fixes.