Or maybe you run a script to periodically check for updates for your favorite apps, scraping the apps page on f-droid website, and downloading updates when available.
You’re assuming F-Droid will alert users to updates. So F-Droid settings should give a warning if users change “Automatic update interval” to “No automatic app updates”. Or remove that option.
The problem is downloading the full update jar is becoming large, several MB, and processing all that is taking much time/battery. Maybe client options should be added for “only check for updates to installed apps” or “shop for new apps you might want to install” to reduce data and processing requirements or increase only when looking for new apps.