Personal gmail being received on business account emails on the gmail app on my phone.
It might be due to having selected All Inboxes which will show you emails from addresses you have. To fix it if it happens again, click the menu icon in top left of gmail app and choose Inbox instead of All Inboxes to only see emails from one inbox at a time.
You can switch between google accounts using the top right icon in the app which is your account icon(the one that is colored and has first letter of your name). Then you will see something like: