What remote control system are you using for your TV/Arc?

I have a Logitech Harmony system, and somewhere buried in the setup for my TV is a volume level for when it gets turned on. Oddly, I have it set to two different levels, based on which TV I am using.
 

The Arc, of course, mirrors the volume setting that it receives from the TV via ARC or eARC. 

Harmony 665 IR remote. Theirs no settings with this Harmony remote. Maybe it's a eARC problem, I will look up what that is. I may consider not using the HDMI for sound if the Sony TV is the problem.

Yea, it’s not in the remote, it’s in the software used for programming the remote, although I do have the puck based system, so it may be different for the ones that don’t use the puck. But it may be worth delving in to the Harmony support site to see if that is a feature associated with your particular remote. As I say, it’s relatively hidden, as memory tells me, in the set up software. I’m not sure I would have found it without a reference doc. And it’s been so long ago, I honestly don’t recall where it exists, just that I was annoyed at having to search for it. 

What happens if you turn off the Control for HDMI setting on your TV?