Tab focus causes brief play

[asdgfd]

When a video is middle clicked (opening in a non-focused new tab), it seems to work as expected (though, the tab's tab has an audio icon as if it were playing). But when you click the tab to bring it into focus, the tab begins playing for perhaps a couple seconds, then stops, sometimes appears to reload, but eventually the video stops like it should be when the page was opened. If I left click the video instead, opening the video page in the current active tab, then everything works as expected.

[asdgfd]

An update. It doesn't seem to be doing this anymore for the past 24-ish hours. I'm uncertain what has changed.