Posting mulitple items to a pubsub node with the same ID will cause a new ID to be generated for the item instead of overwriting the item.
New ID is only created when it is not supplied by the publisher. A duplicate id will overwrite the old item.
I only had version 1.12 of the spec to go by, so it is quite possible that this should go as a subtask of OF-25, which is what I did with other tasks that I knew were related to version updates.
According to 1.12, if a new item is published with the same id as an existing one, it must overwrite the existing one. I checked the diffs for changes between versions and I did not see this listed as a change between 1.8 (which I believe is the currently supported version) and 1.12
Patch looks good to me. Patch is not doing an actual update but a remove and create so we are not keeping a creation and updated date which would be a nice thing to have.
FYI, more than a Bug this issue is an enhancement. The version of pubsub that was implemented didn't support updates of items but just add and remove.
This patch is the fix for and OF-17.