I am the duke of Savoy and I started a faction to gain independence from my liege. However, King Heinrich Salian IV got high tyranny - he kept trying to imprison smaller members of my faction and ended up being replaced in a quiet coup by the duke of Provence. But before the duke of Provence became emperor, he was also part of my faction. Now, an year after his accession, he is still part of my independence faction. When I initiated the demand for independence, he gave independence to my league without any bloodshed. Does the game not implement the restriction that the emperor cannot be part of factions against himself?