It appears every few times I open the app and the usual android back button doesn’t make it go away, and there is no cancel button. What you have to do is toggle the toggle, then the button will change to “do not back up” and then you can press it. It annoys me how easy this makes it to accidentally turn on backup.
Yeah, I had a photo album back when I regularly used Photos, and for some reason the photos would be backed up and the older ones would stop loading on my device? Which was a problem as I don’t have any cellular data. It still happens for some reason, even though I no longer have backup enabled.