The jstest indexbg_updates.js fails with duplicate key error when executed on a mongodb instance started with Mobile storage engine.
[MongoDFixture:job2] 2018-01-09T01:09:30.890+0000 I COMMAND [conn62] command indexbg_updates.$cmd appName: "MongoDB Shell" command: createIndexes { createIndexes: "coll", indexes: [ { key: { field0: 1.0 }, name: "field0_1", background: true } ], $db: "indexbg_updates" } exception: E11000 duplicate key error index: index-36-3171480302421944339 dup key: { : null } code:DuplicateKey numYields:223 reslen:154 locks:{ Global: { acquireCount: { r: 224, w: 224 } }, Database: { acquireCount: { w: 224, W: 2 }, acquireWaitCount: { W: 2 }, timeAcquiringMicros: { W: 7691 } }, Collection: { acquireCount: { W: 224 }, acquireWaitCount: { W: 224 }