Apps launch automatically after update in Google Play Store

As answered by devconsole in the comment.

If you want to find out which app is responsible run adb logcat, look for ActivityManager: START u0 {act=android.intent.action.MAIN ... from uid xyz on display 0. Note the uid number, then run adb shell "dumpsys package" to find out what app that uid belongs to.

My case was Mr Jump game.

After a couple of days and a lot of searches and tests, I figured out that a game named "Zombie Tsunami" was the cause. Deleting all data and uninstalling it fixed the problem.

Maybe start by deleting some games.

The solution for me was to delete the TVSMILES UK app. Once that app was deleted, updates didn't auto-open apps.

I believe you have an app installed that monitors other apps.

For example, an app called Earn Talktime does the same. These apps launch other apps (on installing and updating) for monitoring whether that app was installed through their offer or not.

Simply uninstall any app like that and the issue would be gone.

It's a Play Store bug.

Uninstalling updates of the Play Store in settings should fix the issue. It is drastic but app opening every time you update it is annoying.

This fixed my issue when wiping cache partition did not.

Do a cache partition wipe, as described here: https://support.google.com/nexus/answer/2668187?hl=en.