UITextView scrolls down on iPhone X on every rotation from landscape to portrait

Number:rdar://38259129 Date Originated:08-03-2018
Status:Open Resolved:
Product:UIKit Product Version:iOS 11.x
Classification:Bug Reproducible:Always

— UITextView scrolls down on iPhone X on every rotation from landscape to portrait, even though it was scrolled to top initially.

Steps to Reproduce:
1. Open the attached sample project.
2. Build and run on a portrait iPhone X simulator or device.
3. **Observe**: full-screen text view (yellow background) is scrolled to top.
4. Rotate to landscape.
5. **Observe**: text view is still scrolled to top as expected.
6. Rotate back to portrait.
7. **Observe**: text view is slightly scrolled down. **Expected**: text view should still be scrolled to top.

Rotating back and forth scrolls the text view further and further down until it reaches the bottom of the content.

Expected Results:
— If the text view was scrolled to top it should stay scrolled to top after rotations.

Actual Results:
— Text view gets scrolled down on every rotation from landscape to portrait.

—  Xcode 9.2 (9C40b)
—  iOS Simulator 11.2 (15C107), iOS 11.1.2 (15B202)

Sample project: https://github.com/glebon/TextViewRotationBug


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