[iOS] Screen orientation change do stall application for 15 seconds (iPadAir4)

Only seen on iPad Air 4th generation !

1. On iPad Air 4th generation. (iOS 14.7.1; 14.8.1)
2. Compile "chip" (40.000 chips) example using .pro project file (qmake)
3. Change orientation from Portait to Landscape
4. Rotation occurs but application is stalled for 15 seconds

Observations:

• Debug and Relase mode have issue.
• Placing a breakpoint in Chip:paint() and resume execution immediately does not stall the application. (breakpoints may hide the issue)
• Compiling with CMake breaks application's available geometry to (0, 0  480x320) instead of correct (0, 24  1180x776), but have no issue: maybe because max(width,height)<776