2.1.0 breaks playback - prune/seek bug

Created by: richardbushell

@AkamaiDASH Thanks to you and all concerned in your continued efforts, so much appreciated. We have just tried latest 2.1.0 release and it causes a major bug for us across all browsers for our content. When playback gets to about 1 minute, the log shows prune buffer followed by seek back to 30 seconds, so playback just jumps back 30 seconds. Tried multiple MPDs, here's one: https://living.video/MPD/chaucerbarn.mpd Same thing happening on Dash Nightly Player. This is a very recent bug introduced in the RC stages pre-release. I have a copy of nightly dist build files from 6th April and they work perfectly (I haven't tested in the 9 days subsequently). If you can verify and reproduce, it should be relatively easy to track most recent commits and rectify, but this is a very significant break if it affects others content in the same way.