The Zend Server doesn't actually use APC, instead using it's own implementation - the "Zend Data Cache". There appear to be some subtle differences between them.
One thing that the ZDC has is 'namespaces', where you prefix a key with a '{name}::', and then you can remove all keys that start with that prefix.
It may be that there is a bug when there are two (non consecutive) colons in the string. In the meantime, it's easy enough to simply tweak the structure of the key to avoid the problem.