Uploading em-mongo-0.4.3 ruby gem base64 encodes the version

For some reason when the 0.4.3 version of the em-mongo gem (https://rubygems.org/gems/em-mongo/versions/0.4.3) is uploaded to Nexus the version gets base64 encoded (see the screenshot from 3.19.04 PM).

In the Nexus log the upload starts off fine:

2019-08-14 21:15:25,937+0000 INFO  [qtp1369391473-3526]  admin org.sonatype.nexus.repository.upload.internal.UploadManagerImpl - Uploading component with parameters: repository="hosted-gems" format="rubygems" 
2019-08-14 21:15:25,937+0000 INFO  [qtp1369391473-3526]  admin org.sonatype.nexus.repository.upload.internal.UploadManagerImpl - Asset with parameters: file="em-mongo-0.4.3.gem" 

This manifests in certain builds that use bundle install with the following error:

Retrying dependency api due to error (2/4): ArgumentError Malformed version number string MC40LjM=

MC40LjM= being 0.4.3 in base64.

This issue is reproducible most of the time, but I've also seen it get the version right in some places (like the package name or the associated gemspec name) while still being wrong in others (like the gem name). See the screenshot from 3.26.46 PM.

There might be other gems that are hitting similar cases as this.