BrowserWindow(0) under Browser("edge") could be missing sometimes

When the BrowserWindow(0) is disappeared, there will be a new object called UIAObject("Microsoft_Edge"); however, I dont know how and when this will happen. When I use BrowserWindow(0).Maximzie() function, it would fail all my tests. Althought UIAObject("Microsoft_Edge") can maximaze the browser window too, but it is not existed permanetly either. Has anyone seen this before? Any idea or suggestion to handle it? 

Thanks in advance!