>>> UNRECOVERABLE FATAL ERROR <<<

Unsupported operand types

/phab_path/phabricator/src/applications/owners/storage/PhabricatorOwnersPackage.php:213

I created a diff using arc diff --raw, then added the diff to a revision and pressed Save on that form. Then I got this error. It looks like the diff got added to the revision just fine.

I also got this error when running arc diff to create the revision initially. I ended up with a revision, but the reviewers didn't get set.