How to reproduce:
1. Download and open the attached project
2. Enter Play mode
3. Observe the brightness of the spheres in the Play view
4. Build and deploy the project for iOS
5. Observe the brightness of the spheres in the device

Expected outcome: The brightness of the spheres do not differ between editor and iOS devices
Actual outcome: The brightness of the spheres differ between editor and iOS devices (slightly darker on iOS devices)

Reproduced with: 2021.3.37f1, 2022.3.25f2, 2023.2.19f1, 2023.3.0b10, 6000.0.0b16
Reproduced with: iPad 6th gen (iOS 17.2)
Could not reproduce with: iPhone 12 Pro (iOS 14.4.1), iPhone 13 Pro (iOS 16.6.1)

On the attached project the main light specular appears darker on my iPad Pro 12.9 2nd gen, while on editor and on my iPhone X appears as expected.
You can see the difference on the images attached (the 4:3 being from the iPad).