Originally Posted by signal
Just as a followup, I opened a ticket and it turns out this was normal behavior. The items were part of a subgroup and they won't get cleared out until you finish all tasks in the group.
Sorry about any confusion: it's true that those tasks shouldn't move out of their group in the Inbox, because that would move them out of their group's context—and I think that's what the response to your ticket was addressing.
But unless your view is showing completed items, they shouldn't be displayed in the Inbox after cleaning up. In other words, yes, there is a bug: the inbox should honor the active/remaining view filter just like other sections of the list do.
Before 1.8, it used to be impossible for the Inbox to contain any completed items after cleaning up: all completed individual items would be moved out into your Miscellaneous list, and all groups (whether complete or not) would be promoted into their own projects. But in 1.8 we decided that automatically promoting Inbox groups into active projects was a bit presumptuous: yes, grouped items might in fact be a project, but if they're in the Inbox we should leave them there until you explicitly decide you're ready to commit to them.
But when we made this change, we apparently didn't catch this particular case: the Inbox never had to filter out completed items before (since they were all moved out of it on clean up), so it simply doesn't have any logic in place to do that. We'll fix it.