After getting into details with our supplier, we learned that this issue was caused by a change in the configuration of the router that serves our cluster, without any notice from our supplier. That change has been rolled back and they have ensured us that they will let us know in advance about such changes.
We've also discovered that some of the public pages weren't correctly served from the cache as expected and we're investigating what has happened. We'll get back to the affected customers on a case by case situation, when this situation is resolved.
For any other questions, don't hesitate to get in touch with us at email@example.com