AWS Beanstalk deployment failing - missing bucket_name

Within the last few days Travis deployments to AWS Beanstalk have been failing with a persistent missing bucket_name error. The bucket_name property is provided in the .travis.yml file and is correct in regards to the AWS details.
I have noticed that in the “View Config” link next the builds logs, the actual build file that is generated from the script and sent to AWS is wrong.
https://travis-ci.org/p00gz/frontend/jobs/612649299/config
It is actually showing a bucket property, instead of a bucket_name property. I have checked previous builds and the file shows the correct bucket_name property.
Has something changed in regards to this setup? Or is this a regression?

Thank you!