Weird uitableview behaviour in iOS11. Cells scroll up with navigation push animation

This is due to UIScrollView's (UITableView is a subclass of UIScrollview) new contentInsetAdjustmentBehavior property, which is set to .automatic by default.

You can override this behavior with the following snippet in the viewDidLoad of any affected controllers:

    tableView.contentInsetAdjustmentBehavior = .never

https://developer.apple.com/documentation/uikit/uiscrollview/2902261-contentinsetadjustmentbehavior