iOS app crash when device rotate... [UE 4.19 ~ 4.21]

Crate blank project with UE 4.19 and set available all orientation.


launch on iphone. (ipad has no crash.)
after splash screen,
rotate 90 degree
portrait → landscpae → portrait → landscpae … or landscape → portrait → … repeat.

then crash with some log (my device is iphone 5s)

Is anybody suffer this rotation crash problem?
or is it just me?

It was fine until UE 4.18 .

reproduce on 4.21.0 Preview version .

only iphone not ipad.

Landscape -> portrait is OK.
portrait -> Landscape is Crash.

and on 4.20.3
some iphone (5s) has crash problem when few time rotate device.( portrait → Landscape → portrait repeat…)

you should report this here: Unreal Engine Community

The same in 4.21.1. Here an open issue with target fix set to 4.22: Unreal Engine Issues and Bug Tracker (UE-65091) .