Immediately after switching the page, it will work with CSR.
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Then again, this app was written with SwiftUI, which hasn't received some handy features before macOS 12 and is still way behind AppKit.
When I see an app that's not compatible with the second most recent macOS, I assume the dev either didn't know better or they were too lazy to write workarounds / shims for the latest-and-greatest shiny stuff.