The problem seems to be that Phabrictator does not recognize the raised concern as an audit, so it does not present the option to resign from the audit.

Reproduction steps:

• Open a commit in Diffusion that you have authored yourself
• Raise a concern
• Try to remove the concern from the commit using the 'Action' dropdown

Expected result:

• There is a 'Resign from audit' option in the dropdown

Actual result:

• There is no 'Resign from audit' option in the dropdown

Version information:

phabricator e4c6ae5345188c26f30eb9533270575316ed51f5 (Nov 3 2016)
arcanist e17fe43ca3fe6dc6dd0b5ce056f56310ea1d3d51 (Oct 22 2016)
phutil 1961d5518822d88e74c2635e4374fc1e6be8160a (Oct 28 2016)