I'm not able to reproduce this issue. Can you provide us with a sample page and video stream(s)?
We've looked into this further and have discovered that if we use the copy of Viblast that is on your demo page, then the issue goes away. It looks like our version of the Viblast player is out of date. Do you have a link we could use to always get the latest version of Viblast?
You can use the link from the email you received from us. It contains the latest version. You can check your Viblast version by calling Viblast.version().