Created attachment 329050 [details] Crash Log This assertion failure has shown up on several different test but the most recent was media/track/track-cue-rendering-tree-is-removed-properly.html on El Capitan Debug. Attached is the stderr and the crash log from this particular crash. build: https://build.webkit.org/builders/Apple%20El%20Capitan%20Debug%20WK2%20(Tests)/builds/4568 https://build.webkit.org/results/Apple%20El%20Capitan%20Debug%20WK2%20(Tests)/r225753%20(4568)/results.html https://webkit-test-results.webkit.org/dashboards/flakiness_dashboard.html#showAllRuns=true&tests=media%2Ftrack%2Ftrack-cue-rendering-tree-is-removed-properly.html
Created attachment 329051 [details] stderr The standard error
<rdar://problem/35981299>
Is this a duplicate of bug 180677?