Ansich good receiver, unfortunately with sound dropouts

Possession of the receiver also been about 1 week. I run it in stereo mode on two Teufel Ultima 40 Mk2 speakers. Works flawlessly, AirPlay function is great as the rest. Purchase was crucial for me that he is flat and fits on the shelf. He feels very high quality. Only the remote control has a favorable effect in my eyes.

Initially had the problem that the receiver turns off automatically after a certain time look at TV. Background is the receiver has a sleep function which eliminates him when it receives no signal for a set time. I have a TV with built-in receiver and thus feed the sound back on the HDMI cable (ARC). But the receiver does not recognize that and thinks he does not get a signal and switches off. Problem can be easily remedied in which one provides the Auto Sleep Off.
Furthermore, I had a problem that the receiver has turned on suddenly, that was because of the AutoUpdate feature of my Samsung TVs, which probably turns short in the update search and therefore the receiver. Did the update switched on Manuel and well.

That with the switching occurs according to Google only with Samsung TVs.

Addendum:
Unfortunately, my AV receiver sporadic sound skips airplay, Internet radio as well as FM Radio had repeatedly (thus may be excluded WLAN problem). Sound is then suddenly for 1 minute away, and then it works again. Have installed the latest software. Initially much my suspicions to a power strip, as well as I had connected the receiver to an extra supply, the problem still occurred. Have tried some reset.
Property me then Amazon can deliver a replacement unit (worked perfectly and quickly folded), unfortunately, this problem occurs even when this receiver on. Very pity ansich would the Marantz a super unit, only with this problem for me unusable.
Will now switch to another brand.