I always multitask on my phone. I open app-A, click the left button to see all of my running apps, open up app-B, and so on. A while ago (to be honest, only on Android 9), my apps would restart whenever I go back to them, even though they are running in the background. Sometimes they don't restart, but more often than not, the restart as if I am opening the app for the first time. Before, I could handle it but now it's just gotten so annoying. Especially if I am using a map app and switching between apps to copy the address or information down - just to go back to the map app and see it reset and having to write the info down all over again.