Been have this issue for quite a while.
Example: let's say I have an app that uses the File Picker to pick an image from my DCIM/camera directory. If I test the app with companion (2.74/u) if I spend longer than a few seconds picking an image, companion disconnects.
The same happens for other activities, e.g going out to the native browser, using activityStarter to PICK/GET content, or simply switching to another app on the device, e.g. to check messages.
Only happens with companion, no issues with compiled apps. Tested on Android 15 Pixel 8a, and on Android 13 Pixel 8 Genymotion Emulator.