unless the pop of the region changes (when food/pop rebalance kicks in).. and the titles system is based on pop... ie.. you get a different title because the region has changed...
eg.. avengmil (townsland, bt., 10k+ pop.. and at max) used to have an earl, before pop/title changes. now it has a margrave (alongside all cities)... the other townsland, mio dupaki (5k+ pop... max is not far off that), has a viscount... riombara use complex titles.. don't even ask me what mio's title was before...
cjelegy (10k+ rural) has an earl.. could have sworn i saw lopa having an earl too at some point before when the titles were flipping every day... now it's 8k pop rural and has a viscount. (eh... i hope title doesn't change due to current pop, as opposed to max pop...)