On an arm64 Apple Silicon Mac, the published gen_snapshot_* binaries are x86_64 and therefore run with Rosetta translation.

./iOS/gen_snapshot_arm64:                  Mach-O 64-bit executable x86_64
./iOS-profile/gen_snapshot_arm64:          Mach-O 64-bit executable x86_64
./iOS-release/gen_snapshot_arm64:          Mach-O 64-bit executable x86_64

Compile iOS gen_snapshot_arm64 as arm64, and publish in the arm64 Flutter install (artifacts.zip), as well as the macOS desktop artifacts that get curled when upgrading on an arm64 Mac.

macOS issue was #101138