Comment 1 for bug 1729930

The lease docs and transactions look OK, so I suspect there really is a lot of contention on the lease docs.

The Juju 1.25 branch has a few issues that would cause this:
 - when the leadership manager dies, it remains dead and is not restarted automatically
 - there are potentially many leadership managers running concurrently, within the same process, trying to maintain leases

It's possible that those many leadership managers are each making changes to the same clock document; there's a single clock document for all applications/services.