When tapping on a www .renshuu.org/... link (on a non-renshuu domain) with the iOS app installed, Safari always asks Open in "renshuu"? Selecting "Open" invariably opens the app showing the "Choose a way to sign in" splash screen despite me being signed in; tapping "Sign in with email" then navigates to the dashboard without asking for account credentials, ignoring the original link.
Same problem, minus the initial confirmation, happens with www .renshuu.org links inside Discord (not sure if Discord ever asked whether I want to open the app or a browser).
new.renshuu.org and app.renshuu.org links (both domains appear in web search engine results) are not associated with the app and hence not affected.
(bonus bug: the forums appear to rewrite www .renshuu.org (without the space) in post text to app.renshuu.org).