Ran into this too. With macOS 26 (Tahoe) + Xcode 27 + Device Hub I got only iOS 26 simulator devices to sync with iCloud Drive. On this weekend I upgraded macOS to version 27 (Golden Gate) and Xcode 27 + iOS 27 simulator devices sync fine with iCloud Drive. 🤷‍♂️

One more thing. The CoreML-compiled model downsampling torch.nn.Conv2d with stride (16,1) and kernel (16,1) has similar issues with ANE-processing. Upon iOS runtime initialization the model compilation does not give any console warnings or errors but everything just hangs without any remarks of anything. Changing 16x downsampling to 4x+4x solves that hang-issue.

This particular issue was caused by the upsampling path of the model having torch.nn.ConvTranspose2d operations with stride (16,1) and kernel (16,1) - for some reason ANE-compiler did not like them. Resolved by changing 16x to 4x+4x operation instead. Furthermore, ANE is 16-bit only. CoreMLTools may compile your 32-bit model without issues but loading the runtime model on iOS/macOS will not be assigned on ANE.