, Click on 'Committed' column. Wait. See crash:
TWiki detected an internal error - please check your TWiki logs and webserver logs for more information.
Day '84' out of range 1..30
column can not be sorted in this
particular topic. All other columns sort just fine. A look into the server's error log might reveal more information (I have no access).
However, I re-classify the priority as "Normal". This column contains lots of deeper magic (HTML tags, spreadsheet-calculations) and the topic is no distribution topic.