How to reproduce:
1. Create an empty 3D project (Used URP Core)
2. Build for iOS
3. In the parent directory of the Xcode project, create a “Podfile“
4. Modify the “Podfile” to contain:

• platform :ios, '13.0'
• use_frameworks! (or use_frameworks! :linkage => :static)
• pod 'UnityAds', '4.16.2'
• pod 'IronSourceSDK', '9.0.0.0'
• pod 'IronSourceUnityAdsAdapter', '5.1.0.0'

5. In the parent directory, perform a “pod install“
6. Open the “Unity-iPhone.xcworkspace“ in Xcode version lower than 16
7. In the “Build Settings“ make sure that “Always Embed Swift Standard Libraries“ is set to “Yes“
8. In the “Unity-iPhone.xcodeproj“, create a new Swift file
9. Build

Expected result: Build does not fail
Actual result: The build fails in the UnityFramework target due to missing Swift runtime symbols

Reproducible with: 6000.0.62f1, 6000.2.12f1, 6000.3.0b10 (Unity Ads 4.16.2)
Could not test with: 6000.4.0a5, 6000.5.0a1 (“framework 'ISUnityAdsAdapter' not found” error thrown instead)

Reproducible environment: macOS 14.5 (M1)
Not reproducible environment: No other environment tested

Workaround: Upgrade to Xcode 16 and up