Couch Conflict leads to 500 on user cleanup

Jul 24 20:10:15 orangutan webapp[18600]: Started DELETE "/1/users/2de458aea30efc6644d86dd5104ac2f3.json?identities=destroy" for 0.0.0.0 at 2017-07-24 20:10:15 +0000
Jul 24 20:10:15 orangutan webapp[18600]: Processing by Api::UsersController#destroy as JSON
Jul 24 20:10:15 orangutan webapp[18600]: Parameters: {"identities"=>"destroy", "version"=>"1", "id"=>"2de458aea30efc6644d86dd5104ac2f3"}
Jul 24 20:10:20 orangutan webapp[18600]: Completed 500 Internal Server Error in 4550ms
Jul 24 20:10:20 orangutan webapp[18600]: CouchRest::Conflict (409 Conflict):
  app/models/token.rb:69:in `touch'
  app/models/token.rb:53:in `authenticate'
  app/controllers/controller_extension/token_authentication.rb:13:in `token_authenticate'