Why is Google's Play Store suddenly trying to update apps installed via F-Droid?

Historically, Google did not mess with Android apps installed via the open source F-Droid project . Suddenly, however, Google's Play Store is now trying to update apps installed via F-Droid. There are obvious privacy implications (Google is now likely aware of which F-Droid apps you have installed), but also significant security implications (F-Droid has a stellar security reputation, whereas Google has a deplorable security reputation). Given that, to my knowledge, Google's Play Store does not obtain files from F-Droid repositories, it stands to reason that it likely overrides F-Droid's APK trusted files with Google's untrusted APK files during any updates. Can anyone confirm this hypothesis and shed any light on why Google's Play Store is suddenly trying to update apps installed that the user installed via F-Droid?