I want to share my personal experience on the issue with Moto G3 that I faced repeatedly.
The issue is like :
1. The home button will not be working
2. Incoming calls will not come, the caller will receive either a busy tone or Ring and call drop. But you will be unaware of this.
3. Notification bar fly down menu will not come down
4. You will not be able to switch between the apps, Recent apps button will not respond.
For all the above issues there is a solution that i personally executed and RESOLVED the issue.
You need to Factory Reset the Motorola device / Android device to bring it to normal state.
Before Factory reset you need to back up all your all as Factory reset will erase user information.
HOW to Factory Reset your Moto G3
Use Volume Up / down buttons for Navigation, Power button for Selection.
After the reset your mobile will behave as brand new device where you need to setup your account and install all the apps.
This will bring back your Home Button , Notification Bar and Recent apps functionalities.
These are the steps that are officially provided by Motorola. Here is the link to check the same.