Inappropriate wi-fi password confirmation requests and related memory leak

[jeremy-list]

To replicate:
1: Connect to a Wi-Fi network with 75% signal strength or less

Expected results:
Network Manager should remain connected as much as possible, and automatically reconnect when necessary.

Actual results:
The Wi-Fi password confirmation dialog is repeatedly shown even when the Wi-Fi password has not changed. The memory-consumption of nm-applet increases each time, often up to 200MB over the course of 8 hours.

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: network-manager-gnome 1.2.6-0ubuntu0.16.04.3
ProcVersionSignature: Ubuntu 4.8.0-45.48~16.04.1-generic 4.8.17
Uname: Linux 4.8.0-45-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.6
Architecture: amd64
CurrentDesktop: Unity
Date: Thu Jun 15 14:28:52 2017
EcryptfsInUse: Yes
IfupdownConfig:
 # interfaces(5) file used by ifup(8) and ifdown(8)
 auto lo
 iface lo inet loopback
InstallationDate: Installed on 2017-03-04 (102 days ago)
InstallationMedia: Ubuntu 16.04.2 LTS "Xenial Xerus" - Release amd64 (20170215.2)
IpRoute:
 default via 192.168.1.1 dev wlp2s0 proto static metric 600
 169.254.0.0/16 dev virbr0 scope link metric 1000 linkdown
 192.168.1.0/24 dev wlp2s0 proto kernel scope link src 192.168.1.6 metric 600
 192.168.122.0/24 dev virbr0 proto kernel scope link src 192.168.122.1 linkdown
NetworkManager.state:
 [main]
 NetworkingEnabled=true
 WirelessEnabled=true
 WWANEnabled=true
SourcePackage: network-manager-applet
UpgradeStatus: No upgrade log present (probably fresh install)
nmcli-nm:
 RUNNING VERSION STATE STARTUP CONNECTIVITY NETWORKING WIFI-HW WIFI WWAN-HW WWAN
 running 1.2.6 connected started full enabled enabled enabled enabled enabled