Retriggering the test [shows](https://treeherder.mozilla.org/#/jobs?repo=autoland&searchStr=android-em-4.3%2Creftest&fromchange=2fcf4972c072&tochange=14d818778beb) that it was in fact bug 1404868. Prior to bug 1404868, the failing test was test 5 of 273 in the run; after the change it was test 3 of 272. So it seems like moving it earlier in the run may have trigger this somehow.
Bug 1571222 Comment 9 Edit History
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Retriggering the test [shows](https://treeherder.mozilla.org/#/jobs?repo=autoland&searchStr=android-em-4.3%2Creftest&fromchange=2fcf4972c072&tochange=14d818778beb) that it was in fact bug 1404868. Prior to bug 1404868, the failing test was test 5 of 273 in the run; after the change it was test 3 of 272. So it seems like moving it earlier in the run may have triggered this somehow.