Ion-slides not displayed correctly on some iOS devices

I’m trying to upload my app to App Store, but in some iOS devices the ion-slides does not shown correctly.

It seems that the problem is the IOS version.

Bad - iPad 9th Gen (iOS 15.0)

Bad - iPad Air 4th Gen (iOS 15.0)

Ok - iPadPro 11-inch (iOS 12.4)

Anyone have an idea why this happens?

try to migrate to swiper (check out the migration procedure : Ion-Slides: Mobile Touch Slider with Built-In & Custom Animation )