Regression: UINavigationBar with prompt doesn't animate push/pop

Number:rdar://36877929 Date Originated:25-Jan.-2018 09:15 PM
Status:Duplicate/34546437/Open Resolved:
Product:iOS + SDK Product Version:11.2
Classification:UI/Usability Reproducible:Always
On a UINavigationBar with prompt, when a view controller (also with prompt) is pushed, the navigation bar doesn't animate the title and back button.

Steps to Reproduce:
Build and run the attached sample project.

Expected Results:
When "Push" is tapped, the navigation bar should animate its content. When going back, the content should be animated likewise.

Actual Results:
Neither content is animated.


When the prompt is removed, the animation works as usual.

Also, a CGPostError is thrown (I've enabled a break point for that) and an error is logged:

[Unknown process name] CGAffineTransformInvert: singular matrix.

This worked fine in iOS 10.3.


Please note: Reports posted here will not necessarily be seen by Apple. All problems should be submitted at before they are posted here. Please only post information for Radars that you have filed yourself, and please do not include Apple confidential information in your posts. Thank you!