Thanks yes I can confirm that behavior exactly you described this.
The official plugin above when used permanently suppresses the selected categories for all users. I still think it at the very least have it’s own official plugin page - it’s still useful. Maybe on the plugin page described the default discourse behavior as you explained it and then explain what additional features the plugin provides.
That kills 2 birds with one stone (pardon the horrific expression) - 1. explains how default latest category suppressions work and 2. provides an option to expand on the behavior if required.