I saw a screenshot in the questions channel from Mangoishere that non active residents can't be set as town mayors anymore.
This change literally only hurts the server with how sieges currently work. To have a good and defendable fort, you need to ideally have 2 defence claims on opposite sides of the fort. The enemies need to have a claim for a siegebase to siege it. This is ideally 3, but for easier sake lets say 2 towns per fort.
Pretty much any player that cares about not living underground does NOT want to be the mayor of a siegebase or defence town.
If you want to get rid of proxy mayors, I have a suggestion on how you do so:

The reason players have proxy mayors is that no one wants to live inside siegebases or defence towns as you cant build anything above ground unless you want to sacrifice space to park movecraft. The by far easiest solution to getting rid of proxy mayors is adding a new type of town that is held BY THE NATION it is in. This would mean that a siegebase does not need to be held by an actual player, but rather by the server. This would get rid of about 90% of proxy mayors and would be a nice quality of life change for those people that don't have a lot of friends with a minecraft account. You could do it that a nation can buy an amount of towns that it can hold as a nation or that the upkeep is higher than if it was a normal mayor, so there is still a downside of not having some actual player live in the town.