Thanks for the reply and good questions; I should’ve included in my original post.
Files are all mp3 audio. The reset behavior occurs only in Chrome. In Safari, the progress bar is replaced by the text, “Live Broadcast,” and is not clickable. And in Firefox, there is no issue; clicking the progress bar jumps forward and back as expected.
I’m not familiar with the ‘seek’ function but I’ll look into it. And again, this behavior does not occur across all WP installations, just on a couple of older multisite installations.