Happened in two consecutive main test builds (Gerrit change).
1) ReviewHandlerTest::testWithMinParams UnexpectedValueException: Flagged revision with ID 19 exists with unexpected fr_page_id, error: duplicate review /workspace/src/extensions/FlaggedRevs/business/RevisionReviewForm.php:504 /workspace/src/extensions/FlaggedRevs/business/RevisionReviewForm.php:308 /workspace/src/extensions/FlaggedRevs/business/FRGenericSubmitForm.php:192 /workspace/src/extensions/FlaggedRevs/frontend/specialpages/actions/RevisionReview.php:315 /workspace/src/extensions/FlaggedRevs/rest/ReviewHandler.php:25 /workspace/src/includes/Rest/SimpleHandler.php:38 /workspace/src/tests/phpunit/unit/includes/Rest/Handler/HandlerTestTrait.php:164 /workspace/src/extensions/FlaggedRevs/tests/phpunit/ReviewHandlerTest.php:108 /workspace/src/tests/phpunit/MediaWikiIntegrationTestCase.php:518