Please make sure that you can correct entries regarding browser emulation in windows registry - Enabling HTML5 in the Windows .net Player
In 1.7 series, you can set it to use CEF (in Windows display profile), although CEF is generally not recommended and not supported in 1.8 series, streams should work fine with the default IE11 (assuming that it’s set correctly in the registry).
As for layout refresh, it will reload whole layout when the longest running region (region with the longest duration) ends.
If you have ‘Expire modified layouts’ enabled in display profile and make changes to the layout, it may also cut the playback and reload the layout once it downloaded any new files/changes etc.