I was unable to reproduce the error here. I tested with both versions of GitHub and Marketplace, as well as Engines 5.0 and 5.1, but I obtained the result: BUILD SUCCESSFUL in all attempts.
Could you provide me with the complete project log and some additional information such as the plugin version, engine version, system, SDK versions, Java and NDK versions, and whether you are using the marketplace or GitHub version?
One thing I noticed in the packaging log you sent me is that UBT could not find the plugin’s third-party libraries. Could you reinstall the plugin and test again?