Pick up the rifle v2.0

Not sure who owns specific task, system functionality, who has a ball now? The simplest and usually the correct answer to this is You do!

A couple of things that all Scrum teams encounter is a task blocked by an external team - i.e. waiting for question feedback, waiting for review, waiting for approval, waiting for... Does this mean that the external team owns the task now? No - You still do
How to unblock such tasks? There's always a way, here are a few:
   a) Talk about or at least mention all blocked tasks within your team every day on Daily Scrum meeting
   b) Help ScrumMaster to summarize and report all blocked tasks to Product Owner after each Daily Scrum
   c) Make sure you have an ETA for reply from the external team and remind them early and often
   d) If not waiting for approval then attempt to workaround, try to resolve the task yourself vs. waiting indefinitely

Sprint cannot fail because a task was externally blocked because You own the task and your team headed with ScrumMaster have the ultimate responsibility to unblock it on time


What about Scrum unrelated system ownership - who owns support forum, who owns product source code, who owns posted defects? One would think these are all straightforward and implicit but let me still clarify by taking the latest as an example - ownership of all posted defects

Simply think of a posted defect the same as a QA owned Sprint task:
   A) All defects are posted by QA ("tasks" are created by the Scrum team itself); others teams may in some cases create a few defects (Support for customers, developers for engines only) but defect priority ("task" estimate) is provided or modified by the QA team
   B) Defect creator is current owner of the "task" and must follow through to the end - provide additional details, retest, close the defect
   C) If a defect owner is not available to update the defect ("task" is blocked), QA team have the ultimate responsibility to unblock it by taking the ownership vs. waiting indefinitely on external teams to act
   D) If there are defects created by Support and unverified, posted by former colleagues, made obsolete by new product versions, who's "sprint" will fail if they remain blocked indefinitely?