Since you mentioned that this happens on a Zebra device, it could also be related to device-level configuration. For example, settings like battery optimization, kiosk mode, or enterprise device policies may terminate the app process when the application goes to the background.
It may help to check the device logs (logcat) when the app is minimized and then reopened. If the application is actually being killed and restarted, this usually becomes visible in the logs.
If this resolves your issue, please mark the answer as accepted so it can help others facing the same problem.