The default channel policy includes:

            is_child_task :: parent

So that most tasks follow their parents. Many custom channel policies include this, which is recommended.

Build routing in the channel policy is often done by rules like (this is just an example):

       method build && bool target && match target epel-* :: use epel

However if the build task is part of a chain build and the is_child_task rule comes earlier, then that rule will take precedence instead.

I don't know which Koji instance is giving you a problem (perhaps Fedora's?), so I don't know what the channel policy is there. Most likely, the fix is an adjustment to that policy. Please take this up with the administrators of your Koji instance.

If the channel policy in that instance is not being followed correctly by Koji, or if the available policy rules are insufficient to accomplish what is needed, then please get someone to file an issue here with relevant details.

side note: it used to be that channel policy only had target data for a very limited set of task methods (mainly build). With 1.17 (pr #962), pretty much any task with a target parameter (such as chainbuild) will have this data available. This should give admins more flexibility in channel routing.

I confirm that was a problem in hub policy used in Koji deployment at Fedora infrastructure. It was fixed in Fedora ansible.git commit 0fc00d4.