I can't guess why Samsung does that and not to the last input. It's been reported all over so why you write there is nothing wrong with the TV it does appear to default to the wrong input.
Did you try disabling that port? Most Samsungs don't allow this.
Call it in. Seems to be some thing everyone wants.
I have Samsung Smart TV that is connected to Onkya receiver. Receiver is connected on Samsung's HDMI 1. All features works fine but when I go on SmartHub, non of the videos being played online has audio. But when I move HDMI cable to HDMI 2 in Samsung TV, audio works. The only problem is, when I turn off the TV and turn it back on TV defaults to HDMI 1 so I have to keep switching source to HDMI 2 for everything to work. Is there any quick fix on this? I'm pretty sure there's nothing wrong with the TV and the receiver. It's just a matter of configuration. Please correct me if I am wrong.