15" MBP Touch Bar, Radeon 460 2.7GHz 512TB After a few hours of use/a few lid closes and opens later, speakers fail to output any audio. No, system is not muted, app is not muted, and sound output IS set to internal speakers. Sometimes restart fixes. SMC reset always fixes. Anyone else experience the same issue? I searched but could not find one. Thought I'd check with others before going to radar and opening a bug, seems like a firmware issue.