One feature of the SE sites is that many (most?) of the pages will persist their sort and filtering options.
For example, when I click on the Questions link on any of my regular sites in a browser, it always defaults to the Newest sort, because that is how I prefer to read the sites and is the way I more than likely was reading it during my last session.
The iOS app doesn't always do this.
If you goto a site, tap Questions, choose a sort, tap a question, and then tap the back link, the sort persists.
If you goto a site, tap Questions, choose a sort, goto another site, ..., then go back to a site and tap Questions, the sort will be back at Active.
This is inconsistent and annoying. Please persist the sorts/filters during a session and between sessions.