I believe a change might've happened to how macOS 15's pkgbuild works, it seems to no longer infer the version value that should show up in the resulting package's PackageInfo file's top level version field.

we could add an additional field to the options parsing here https://github.com/electron-userland/electron-builder/blob/v25.1.6/packages/app-builder-lib/src/targets/pkg.ts#L156 to cause the args to include an additional --version <value> so that that value becomes non-zero. isVersionChecked is additionally broken by electron-builder's call to pkgbuild without a --version flag passed to it, but we don't want to require that the isVersionChecked option be passed to enable passing --version to pkgbuild.