Uploading via upload mode "Artifact Bundle" never completes

I followed the instructions at https://docs.sonatype.org/display/Repository/Uploading+3rd-party+Artifacts+to+The+Central+Repository up to & including "Uploading an Artifact Bundle to the OSS Nexus Instance". After selecting bundle via "Select Bundle to Upload..." and clicking "Upload Bundle", the "Uploading..." progress bar simply loops and appears never to complete (after waiting several minutes). Attached is screen shot. Tried on latest versions of Chrome & Firefox.

Also attached is bundle jar that I'm attempting to upload.