Chrome Version       : 60.0.3112.90
OS Version: OS X 10.12.6 and MS Windows 10
URLs (if applicable) : (none)
Other browsers tested:  IE 11 and Edge on Windows 10; Safari and Firefox on macOS
  Add OK or FAIL after other browsers where you have tested this issue:
     Safari 10.1.1:  OK
     Firefox 55.0.2:  OK
     IE 11:  OK
     Edge:  OK

1. Go to one of the online video players that use HLS.js to play HLS streams. Tested were:
  http://players.akamai.com/hls/
  http://streambox.fr/mse/hls.js-0.7.11/demo/
  http://demo.jwplayer.com/developer-tools/http-stream-tester/
2. Enter the URL http://acdn-vs.thuuz.com/2mina.m3u8 as the stream to play. If it doesn't start playing automatically, start it manually quickly. (A delay may cause it not to occur.)
3. Observe that about 3 seconds into play, the video pauses for 0.5 to 1.5 seconds then resumes. Each attempt can have slightly different results, and on occasion it doesn't happen at all.

What is the expected result? Video to play smoothly.

What happens instead of that? Video "hiccups" (pauses briefly) a few seconds into it. In some streams it does it more than once.

Additional details:
It is helpful to have DevTools open and in the Console so you can see HLS.js struggling at the point it pauses. (Two of the players above have HLS.js's debug output enabled.)
This issue only happens if browser caching is enabled. If you disable it in DevTools the video plays smoothly every time.
Under Windows 10, the issue never occurs in IE 11 or Edge but it *sometimes* does in Chrome (more rarely than under Mac).
The issue could be strictly in HLS.js's implementation under Chrome, but it is interesting / relevant that it only happens if Chrome's caching is enabled.
The issue does not happen every single time, but on macOS it is >50%. Timing in starting playback can affect the outcome. If HLS.js has time to pre-fetch some segments and get past the trouble spot before playback begins, the hiccup will not occur.