We have a daemon task which is consistently failing (it has failing 1721) times. Attempting to execute the worker task manually provides the following error:
```
> ./bin/worker execute --id 20987313
Executing task 20987313 (PhabricatorApplicationTransactionPublishWorker)...
[2015-11-26 10:59:21] EXCEPTION: (PhabricatorPolicyException) [You Shall Not Pass: Restricted Differential Diff] (Can View) You do not have permission to view this object. // Subscribers can take this action. This diff is attached to a revision, and inherits its policies. at [<phabricator>/src/applications/policy/filter/PhabricatorPolicyFilter.php:590]
arcanist(head=master, ref.master=eeaa176cfc5a), phabricator(head=master, ref.master=b21928599960, custom=1), phlab(head=master, ref.master=cae356731a58), phutil(head=master, ref.master=f0881b37049c)
#0 PhabricatorPolicyFilter::rejectObject(DifferentialDiff, string, string) called at [<phabricator>/src/applications/policy/filter/PhabricatorPolicyFilter.php:507]
#1 PhabricatorPolicyFilter::checkCapability(DifferentialDiff, string) called at [<phabricator>/src/applications/policy/filter/PhabricatorPolicyFilter.php:214]
#2 PhabricatorPolicyFilter::apply(array) called at [<phabricator>/src/infrastructure/query/policy/PhabricatorPolicyAwareQuery.php:244]
#3 PhabricatorPolicyAwareQuery::execute() called at [<phabricator>/src/infrastructure/query/policy/PhabricatorPolicyAwareQuery.php:167]
#4 PhabricatorPolicyAwareQuery::executeOne() called at [<phabricator>/src/applications/differential/customfield/DifferentialChangesSinceLastUpdateField.php:43]
#5 DifferentialChangesSinceLastUpdateField::updateTransactionMailBody(PhabricatorMetaMTAMailBody, DifferentialTransactionEditor, array) called at [<phabricator>/src/applications/transactions/editor/PhabricatorApplicationTransactionEditor.php:2681]
#6 PhabricatorApplicationTransactionEditor::addCustomFieldsToMailBody(PhabricatorMetaMTAMailBody, DifferentialRevision, array) called at [<phabricator>/src/applications/differential/editor/DifferentialTransactionEditor.php:1227]
#7 DifferentialTransactionEditor::buildMailBody(DifferentialRevision, array) called at [<phabricator>/src/applications/transactions/editor/PhabricatorApplicationTransactionEditor.php:2376]
#8 PhabricatorApplicationTransactionEditor::buildMailForTarget(DifferentialRevision, array, PhabricatorMailTarget) called at [<phabricator>/src/applications/transactions/editor/PhabricatorApplicationTransactionEditor.php:2333]
#9 PhabricatorApplicationTransactionEditor::buildMail(DifferentialRevision, array) called at [<phabricator>/src/applications/transactions/editor/PhabricatorApplicationTransactionEditor.php:1048]
#10 PhabricatorApplicationTransactionEditor::publishTransactions(DifferentialRevision, array) called at [<phabricator>/src/applications/transactions/worker/PhabricatorApplicationTransactionPublishWorker.php:21]
#11 PhabricatorApplicationTransactionPublishWorker::doWork() called at [<phabricator>/src/infrastructure/daemon/workers/PhabricatorWorker.php:122]
#12 PhabricatorWorker::executeTask() called at [<phabricator>/src/infrastructure/daemon/workers/storage/PhabricatorWorkerActiveTask.php:171]
#13 PhabricatorWorkerActiveTask::executeTask() called at [<phabricator>/src/infrastructure/daemon/workers/management/PhabricatorWorkerManagementExecuteWorkflow.php:52]
#14 PhabricatorWorkerManagementExecuteWorkflow::execute(PhutilArgumentParser) called at [<phutil>/src/parser/argument/PhutilArgumentParser.php:406]
#15 PhutilArgumentParser::parseWorkflowsFull(array) called at [<phutil>/src/parser/argument/PhutilArgumentParser.php:301]
#16 PhutilArgumentParser::parseWorkflows(array) called at [<phabricator>/scripts/setup/manage_worker.php:21]
```