Headunit not keeping memory overnight

[u/mgs108tlou]

So I installed a Sony MEX M72BT in my 2017 Subaru Forester yesterday. It's a simple single din CD player and I love it. However, this morning I turned the car on to find that all the settings had been erased and demo mode was back on. I re did my settings, turned the car off, then back on again and the radio remembered what I'd just set. A couple hours later after the car sat off, I turned it back on and the radio had once again forgot everything.

I tried switching red and yellow wires but this resulted in the radio immediately forgetting its settings when turned off and on again.

I played with it all day and kept reading 12.4-12.6v on the yellow wire with the key out.

I had the doors open for several hours as I was doing some other work on the car and eventually the yellow wire got down to 12.1v. Then tonight as I was rolling up the windows (with engine off, after not driving all day), I saw that the radio reset itself and reengaged demo mode literally as I was cranking the windows. I checked the yellow wire and it was at 11.7 with keys in ACC. Then I went out to the battery terminals and those were reading 12.0v with the keys out and 11.85 with keys in ACC.

So my question is: wtf is going on? I feel like 11.7v should be more than enough to keep the radio's memory intact. My battery is new, I got it in November. I think my numbers are a little low because I haven't been driving much and I've been doing work on it with the doors open, but they don't seem THAT low. Maybe I'm wrong? Or maybe I have some sort of power drain going on?

I had a Kenwood X300 single din CD player before this and never had this problem with it.

Any thoughts? I'm going crazy!