Pi3 and Onkyo amp - random "no input" when turning on Onkyo

After changing from Denon 1910 to Onkyo TX-RZ900 amp I get “no input” signal over HDMI (it happens every 3rd/4th switch-on of the amplituner). After turning on my amp I just see no picture on the TV - it looks like the hdmi cable would be disconnected. What helps than is a restart of my Pi3 (I plug off power cable) - the I can see the picture. Pluging out and in hdmi cable do not help.
I dont have this problem with other devices (DVD, cable tv, apple tv etc) and also I didnt experience it with older amp from Denon.

I switch on my home theatre system with Logitec Harmony-one remote and Onkyo is turned on at the end (Pi3 is on all the time).
Two hdmi outputs are used in my Onkyo - one for TV and other for projector.

I did not identified/register any circumstances before it happens that would/could influence this problem.

Any idea what could be the cause of this issue? Maybe the problem is that Pi3 is all the time on and it should boot/restart after Onkyo boots up?

Pawel

Try this

http://kodi.wiki/view/Raspberry_Pi_FAQ#TV_is_not_detected_unless_powered_on_first