Fixed: A reason of this issue was that there was not applied "3rd party" patch which adds (into cobbler python scripts) support of ipv6 cobbler systems attributes used in snippets then. Due to it scheduled cobbler system metadata (json file) didn't contain the ipv6 variables and their pre-set values. And finally, usage of not initialized variables (e.g. ipv6_autoconfiguration) caused that cobbler couldn't expand snippet in kickstart script. Space-walk-git: 191f262c0ab0497203428a95231d7b8de170e6d8 If the solution does not work for you, re-assign this bug please.
Spacewalk 2.5 was released.
This BZ closed some time during 2.5, 2.6 or 2.7. Adding to 2.7 tracking bug.