Battery expanded from charging

I purchased a period correct battery from Antique Auto Battery. Not cheap and its been in the car for 14 months. I've probably charged it with the CTEK 3300 eight to ten cycles. Wondering what would cause the battery to expand like it did. I use the CTEK on my other cars and this is the first time I've had an issue.

Anyone have experience when dealing with the above mentioned company on a battery warranty issue? Thanks for any input.