iOS 18 @AssistantIntent's marked with @available crashing on older OS's

Is anyone else seeing their apps crash on iOS/macOS 17.4/14.4 and newer when building a project that simply just includes the iOS 18 @AssistantIntent Macro?

The beta 4 releases still have this problem. There are no notes about this that I have seen in the beta release notes. Crash message shown in console when trying to run on 17.4, 17.5, 17.5.1, etc:

dyld[21935]: Symbol not found: _$s10AppIntents15AssistantSchemaV06IntentD0VAC0E0AAWP Referenced from: <F7A1FEF0-F3B0-379C-A914-D1FB0BA7C693> /Users/jonathan/Library/Developer/CoreSimulator/Devices/CA308F47-BCA8-4429-8599-1BB1CCEAB5B6/data/Containers/Bundle/Application/D7DC8E16-90DB-406A-A521-20F18326E4A7/IntentDemo.app/IntentDemo.debug.dylib Expected in: <88E18E38-24EC-364E-94A1-E7922AD247AF> /Library/Developer/CoreSimulator/Volumes/iOS_21F79/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS 17.5.simruntime/Contents/Resources/RuntimeRoot/System/Library/Frameworks/AppIntents.framework/AppIntents

Obviously, the new Apple Intelligence AssistantIntents only work on the 2024 OS releases. However, even when these new App Intents are marked with @available(iOS 18, macOS 15, *), the app crashes on any earlier OS version. But it runs just fine on iOS 18 and macOS 15...

I would love for me to just have done something wrong but I don’t think I have… Here is the sample project: https://github.com/JTostitos/FB14323923

Maybe it's a compiler issue thats failing to strip out the macro when building for older OS's or an Xcode issue - I have no idea. I just would like to know why its not working and how to resolve it.

Thanks in advance for anyones help...

iOS 18 @AssistantIntent's marked with @available crashing on older OS's
 
 
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