Sorry about that. Updated today....issue still exists:

MAAS Version 2.0.0 (rc4+bzr5187)

Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: 2016-08-11 00:38:03 [-] Unhandled failure in updating lease.
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011Traceback (most recent call last):
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011  File "/usr/lib/python3.5/threading.py", line 862, in run
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011    self._target(*self._args, **self._kwargs)
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011  File "/usr/lib/python3/dist-packages/provisioningserver/utils/twisted.py", line 904, in worker
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011    return target()
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011  File "/usr/lib/python3/dist-packages/twisted/_threads/_threadworker.py", line 46, in work
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011    task()
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011  File "/usr/lib/python3/dist-packages/twisted/_threads/_team.py", line 190, in doWork
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011    task()
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011--- <exception caught here> ---
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011  File "/usr/lib/python3/dist-packages/twisted/python/threadpool.py", line 246, in inContext
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011    result = inContext.theWork()
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011  File "/usr/lib/python3/dist-packages/twisted/python/threadpool.py", line 262, in <lambda>
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011    inContext.theWork = lambda: context.call(ctx, func, *args, **kw)
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011  File "/usr/lib/python3/dist-packages/twisted/python/context.py", line 118, in callWithContext
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011    return self.currentContext().callWithContext(ctx, func, *args, **kw)
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011  File "/usr/lib/python3/dist-packages/twisted/python/context.py", line 81, in callWithContext
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011    return func(*args,**kw)
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011  File "/usr/lib/python3/dist-packages/provisioningserver/utils/twisted.py", line 937, in callInContext
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011    return func(*args, **kwargs)
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011  File "/usr/lib/python3/dist-packages/provisioningserver/utils/twisted.py", line 205, in wrapper
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011    return func(*args, **kwargs)
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011  File "/usr/lib/python3/dist-packages/maasserver/utils/orm.py", line 602, in call_within_transaction
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011    return func_outside_txn(*args, **kwargs)
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011  File "/usr/lib/python3/dist-packages/maasserver/utils/orm.py", line 433, in retrier
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011    return func(*args, **kwargs)
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011  File "/usr/lib/python3.5/contextlib.py", line 30, in inner
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011    return func(*args, **kwds)
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011  File "/usr/lib/python3/dist-packages/maasserver/rpc/leases.py", line 134, in update_lease
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011    lease_time=lease_time, created=created, updated=created)
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011  File "/usr/lib/python3/dist-packages/django/db/models/manager.py", line 127, in manager_method
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011    return getattr(self.get_queryset(), name)(*args, **kwargs)
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011  File "/usr/lib/python3/dist-packages/django/db/models/query.py", line 348, in create
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011    obj.save(force_insert=True, using=self.db)
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011  File "/usr/lib/python3/dist-packages/maasserver/models/cleansave.py", line 29, in save
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011    return super(CleanSave, self).save(*args, **kwargs)
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011  File "/usr/lib/python3/dist-packages/maasserver/models/timestampedmodel.py", line 64, in save
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011    return super(TimestampedModel, self).save(*args, **kwargs)
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011  File "/usr/lib/python3/dist-packages/django/db/models/base.py", line 734, in save
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011    force_update=force_update, update_fields=update_fields)
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011  File "/usr/lib/python3/dist-packages/django/db/models/base.py", line 762, in save_base
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011    updated = self._save_table(raw, cls, force_insert, force_update, using, update_fields)
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011  File "/usr/lib/python3/dist-packages/django/db/models/base.py", line 846, in _save_table
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011    result = self._do_insert(cls._base_manager, using, fields, update_pk, raw)
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011  File "/usr/lib/python3/dist-packages/django/db/models/base.py", line 885, in _do_insert
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011    using=using, raw=raw)
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011  File "/usr/lib/python3/dist-packages/django/db/models/manager.py", line 127, in manager_method
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011    return getattr(self.get_queryset(), name)(*args, **kwargs)
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011  File "/usr/lib/python3/dist-packages/django/db/models/query.py", line 920, in _insert
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011    return query.get_compiler(using=using).execute_sql(return_id)
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011  File "/usr/lib/python3/dist-packages/django/db/models/sql/compiler.py", line 974, in execute_sql
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011    cursor.execute(sql, params)
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011  File "/usr/lib/python3/dist-packages/django/db/backends/utils.py", line 64, in execute
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011    return self.cursor.execute(sql, params)
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011  File "/usr/lib/python3/dist-packages/django/db/utils.py", line 98, in __exit__
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011    six.reraise(dj_exc_type, dj_exc_value, traceback)
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011  File "/usr/lib/python3/dist-packages/django/utils/six.py", line 685, in reraise
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011    raise value.with_traceback(tb)
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011  File "/usr/lib/python3/dist-packages/django/db/backends/utils.py", line 64, in execute
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011    return self.cursor.execute(sql, params)
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011django.db.utils.IntegrityError: duplicate key value violates unique constraint "maasserver_staticipaddress_ip_key"
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011DETAIL:  Key (ip)=(172.16.101.38) already exists.
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011
Aug 11 00:38:03 r6-c1-n1-maas sh[5475]: #011