Lost ID when using XCUITest with appium 1.6 beta3 in IOS

I am trying to get the a textfield element . The input filed have id “Savevalue"
But When I use appium to go to that page and getPageSource. will find the matched XCUIElementTypeTextField have lost the ID and Name. So I can’t findElement by ID or Name.
Anyone can tell me how to avoid it. I need to use id to locate this text filed element.

@xinhuadian if this issue is consistently reproduce, please file issue under https://github.com/appium/appium/issues with as much details possible.