nm-applet constantly prompts for password, leaks memory

Network Manager is constantly asking me for a WIFI password, as frequently as once a minute. I do not get this problem on my phone, even though it is using the same WIFI network. The problem does not occur on other WIFI networks, so I suspect this is a problem with the WIFI network itself, and is possibly not Network Manager's fault. So this is annoying, but liveable.

However, np-applet is also leaking an absurd amount of memory each time I enter my password and click "Connect". It's ridiculous for it to be using up over 2 GB of resident memory, and to be constantly increasing that number, after running for only a few hours.

This is a not a duplicate of https://bugs.launchpad.net/ubuntu/+source/network-manager-applet/+bug/684599. In that issue, which has been closed with a "Fix Released" status, the reports are hundreds of megabytes of memory, not gigabytes, so I suspect this is a fundamentally different problem.

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: network-manager 1.2.0-0ubuntu0.16.04.3
ProcVersionSignature: Ubuntu 4.4.0-31.50-generic 4.4.13
Uname: Linux 4.4.0-31-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.1
Architecture: amd64
CurrentDesktop: Unity
Date: Sun Aug 7 19:08:52 2016
IfupdownConfig:
 # interfaces(5) file used by ifup(8) and ifdown(8)
 auto lo
 iface lo inet loopback
InstallationDate: Installed on 2013-08-26 (1077 days ago)
InstallationMedia: Ubuntu 13.04 "Raring Ringtail" - Release amd64 (20130424)
IpRoute:
 default via 10.2.61.69 dev wlan0 proto static metric 600
 10.0.1.4 via 10.2.61.69 dev wlan0 proto dhcp metric 600
 10.2.61.68/30 dev wlan0 proto kernel scope link src 10.2.61.70 metric 600
 169.254.0.0/16 dev wlan0 scope link metric 1000
NetworkManager.state:
 [main]
 NetworkingEnabled=true
 WirelessEnabled=true
 WWANEnabled=true
 WimaxEnabled=true
RfKill:
 0: phy0: Wireless LAN
  Soft blocked: no
  Hard blocked: no
SourcePackage: network-manager
UpgradeStatus: Upgraded to xenial on 2016-04-26 (103 days ago)
nmcli-dev:
 DEVICE TYPE STATE DBUS-PATH CONNECTION CON-UUID CON-PATH
 wlan0 wifi connected /org/freedesktop/NetworkManager/Devices/0 EHS New Yorker Residence c06e0703-cd04-4294-9f99-8624c834f389 /org/freedesktop/NetworkManager/ActiveConnection/53
 eth0 ethernet disconnected /org/freedesktop/NetworkManager/Devices/1 -- -- --
 lo loopback unmanaged /org/freedesktop/NetworkManager/Devices/2 -- -- --
nmcli-nm:
 RUNNING VERSION STATE STARTUP CONNECTIVITY NETWORKING WIFI-HW WIFI WWAN-HW WWAN
 running 1.2.0 connected started full enabled enabled enabled enabled enabled