Lost Application.Storage content after USB plug to computer

Hello,

I have an issue with Application.Storage, the persistent storage seems to bet reseted after I plug the watch in USB in my computer.
I have the following App.mc :

using Toybox.Application.Storage;

class App extends Application.AppBase {

    function initialize() {
        AppBase.initialize();
    }

    function onStart(state as Dictionary?) as Void {
        var key = "KEY"; 
        System.println(Storage.getValue(key));
        Storage.setValue(key, "OK");
    }

}

function getApp() as App {
    return Application.getApp() as App;
}

This is my test procedure with logs :
// Launch the App
> null // Expected for the first launch
// Exit the App and re-run the App
> OK
// Plug my watch to my computer, do nothing, wait 10sec, unplug the watch, run the App
> null  // The Storage has bet reseted

This behaviour appears on Forerunner 245 and Fenix 7 but not on EPIX Gen 2 and also it not appears in the simulator (all watches)