Agee: "doesn't feel right". (And thank you USAFRet for testing the Powershell script.)
I was looking into some way of reverse engineering the OP's issue. Mostly dead ends but someone with more Powershell experience would likely to be able to set up the necessary logic that checks for a registry key, a service, etc. and if found "on" just turns it "off" again. I.e., button goes back to off again.
Regarding: " I check updates, it says I have to update Windows Antivirus."
What is the exact wording and how is the message presented?
The original intent (Microsoft?) being that automatic updates cannot or no longer be turned "OFF".
Just got it backwards or otherwise ran afoul of "unintended consequences".
Still interested in some possible relationship to "Windows Antivirus". Would expect to see "Defender" in there somewhere.
I think the Windows AV aspect comes in because that is the most often updated section.
If you manually check every day, you're going to see that every day, or every other day.
It's not exclusively the AV.
I'm letting my Transformer (Win 10 Home) run a couple of days on its own, without checking or updating anything. Just to see what happens.
So, a test from Sunday 10 June to Thursday 14 June. No messing with anything related to Updates. Actually, not using it at all, just leaving the laptop ON.
Selection button remains OFF. Cannot cause it to stay ON.
It checked yesterday (Wednesday)
It got its own update on Tuesday, squarely in the middle of the time period.
So, it appears whatever that button says makes no difference.
Seems that button showing OFF is of no import.
One solution is just not use defender and instead us a 3rd party Antivirus like Bitdefender Free whbich will update itself every hour and leave you alone. I use Bitdefender Total Security and it doesn't even bug me for anything. Always in top 3 of AV in tests so its not a bad option.