I got the following reply back from support, go figure
Thanks for reaching out! I’m sorry to hear you experienced this problem with the corrosion of your Hub’s batteries. There is nothing wrong with your Hub or batteries, and this will naturally occur when devices constantly draw power from batteries in a backup capacity.
We definitely apologize for not alerting people sooner but we did recently publish a support article that addresses why this occurs, how to clean the corrosion, and steps you can take to prevent this from happening again. Please check out the following link:
So much for taking any ownership
Rick