jpackage signing on macOS does not work as expected

To reproduce this issue download latest early access build (Build 14-jpackage+1-35 (2019/8/29)) and run command below with assumption that self signed certificate is generated and imported to keychain. These steps are omitted from bug report.

jpackage --package-type pkg --input input2 --output output2 --name Test2 --main-jar DynamicTreeDemo.jar --main-class webstartComponentArch.DynamicTreeApplication --mac-sign --mac-signing-key-user-name openjdk.java.net --mac-signing-keychain jpackagerTest.keychain

Check signatures for produced bundles.
1) pkg is not signed. Unexpected.
2) dmg is not signed. Expected.
3) All binaries including Java runtime is signed with provided certificate. This is unexpected. We only should sign launcher and pkg.