I think that was another attempt by Apple to push users to iOS 26, but after seeing how many people with compatible devices refuse to upgrade, they finally caved in and provided an update.
They caved, but they're still pulling out new tactics to trick users into installing iOS 26.
The new iOS 18 update will _also_ toggle Automatic Updates back on. I had it happen just now on my 13 Mini against my will. I had to go back into settings and very carefully navigate to disable automatic updates.
