Kasina glasses

Hello,
I have a kasina for about 1 year and I am very satisfied with the product. But there is a little problem with the glasses, I replaced the glasses six months after my purchase because it had broken. The glasses were replaced as provided in the guaranteed. Six months after the replacement they are still broken. I noticed that the break is always in the same place as the picture attached to the message.
I take special care to my kasina and I think the glasses may have a manufacturing defect.

Attachment 887