Ohhhhh. um. So you have two separate drivers? I don’t think thats going to work. I bet android UIAutomator can only run one instance on a device.
Instead, Hm. If you first run App1, then tap a link to open the browser. Then you can automate the browser, then tap a button on the browser to return to your app. All with just one driver object (so just one appium session).