Summary:
changelog: [internal]
This looks like a bug where the author did not intend the conversion to boolean. This means that `onlyMutationIsUpdate` was evaluated to true even if more than 1 animation was in the vector.
Reviewed By: RSNara
Differential Revision: D30767172
fbshipit-source-id: 0ef47b65a5d8ef07d774d9e0b358e5642dc0a9ea