The culprit is Apple's 'automatic downloads' feature, which allows you to download both apps and app updates without doing anything yourself.
That's why addressing this setting is crucial for maintaining some level of order across your multiple iOS devices. That said, I really don't need every app I download on my iPhone appearing on my iPad, and vice versa. The benefit of going all-in on the Apple ecosystem is that your stuff is connected across all of your Apple products.
