Hi Jinnyre,
we're running IE=EmulateIE7 / Quirks, because most of our users are still on XP with IE7 (don't ask..) -.-
The issue is happening for all iviews/scenarios as I wrote in my opening post. I tried different iviews which existed before the upgrade and also created a couple of news ones after the upgrade. All of these iViews are affected.
Cheers, Lukas