Adding an entity to a Core Data model prevent Canvas Preview to show

Hello,

I have a SwiftUI application with a Core Data model. This model contains some entities, with properties. The canvas is working as expected, showing the preview.

But whenever I add a new entity, event without any property, the canvas fail to show the preview (event a basic view with only a text view in it). The error message is the following:

Cannot preview in this file - The operation couldn't be completed. Transaction failed. Process failed to launch.

I tried to clean my cache, the derived data folder, reset the simulators, etc. When I click on Diagnostics, here is the message:

Error Domain=FBProcessExit Code=4 "The process crashed." UserInfo={NSLocalizedFailureReason=The process crashed., BSErrorCodeDescription=crash, NSUnderlyingError=0x600002f29dd0 {Error Domain=signal Code=4 "SIGILL(4)" UserInfo={NSLocalizedFailureReason=SIGILL(4)}}}

RemoteHumanReadableError: The operation couldn’t be completed. Transaction failed. Process failed to launch. (process launch failed)

BSTransactionError (1):
==error-description: Process failed to launch.
==precipitating-error: Error Domain=FBProcessExit Code=4 "The process crashed." UserInfo={NSLocalizedFailureReason=The process crashed., BSErrorCodeDescription=crash, NSUnderlyingError=0x600002f29dd0 {Error Domain=signal Code=4 "SIGILL(4)" UserInfo={NSLocalizedFailureReason=SIGILL(4)}}}
==NSLocalizedFailureReason: Transaction failed. Process failed to launch. (process launch failed)
==transaction: <FBApplicationProcessLaunchTransaction: 0x60000186d960>
==error-reason: process launch failed

Any idea why I have that?

Thanks,
Axel

PS: I'm using Xcode 12 beta 6 (also tried on beta 5). I'm on macOS Big Sur (20A5364e).