Quite often when you're sitting you will follow a link (like the kingdom you're at war with, from your kingdom page) and it won't take you to the sit page, but back to your page.

Occasionally it happens with your non-sit province, linking you to a sit page even if you aren't sitting. Occasionally it happens with important pages such as thief or mystic pages, leading you to cast spells/thief ops with the wrong province.