Why don’t they set this to null?
When the leader of a clan has not entered Clash of Clans for 90 days, the game selects a new leader. Members and the leader will receive messages about the rotation throughout the process.
How does it work? 60 days of inactivity: Clan members receive an in-game message informing them that the oldest active person with the highest title will become the new clan leader. 74 days of inactivity: The leader receives a notification about the rotation due to his inactivity. 83 days of inactivity: The leader receives a second notification about the rotation. The entire clan receives a second notification about the rotation. 90 days of inactivity: A new leader is appointed