diff --git a/clients/cli/devices.c b/clients/cli/devices.c
index 58102ed371..aa28678ff5 100644
--- a/clients/cli/devices.c
+++ b/clients/cli/devices.c
@@ -2772,6 +2772,17 @@ wifi_list_aps (NMDeviceWifi *wifi,
 
 	needs_rescan = rescan_cutoff < 0 || (rescan_cutoff > 0 && nm_device_wifi_get_last_scan (wifi) < rescan_cutoff);
 
+	/* FIXME: nmcli should either
+	 *  - don't request any new scan for any device and print the full AP list right
+	 *    away.
+	 *  - or, when requesting a scan on one or more devices, don't print the result
+	 *    before all requests complete.
+	 *
+	 *  Otherwise:
+	 *    - the printed output is not self consistent. E.g. it will print the result
+	 *      on one device at a certain time, while printing the result for another
+	 *      device at a later point in time.
+	 *    - the order in which we print the AP list per-device, is unstable. */
 	if (needs_rescan) {
 		data = g_slice_new0 (WifiListData);
 		data->nmc = nmc;
diff --git a/tools/test-networkmanager-service.py b/tools/test-networkmanager-service.py
index c55955d99d..f6da6e1fd7 100755
--- a/tools/test-networkmanager-service.py
+++ b/tools/test-networkmanager-service.py
@@ -49,6 +49,11 @@ class Util:
 
     PY3 = (sys.version_info[0] == 3)
 
+    @staticmethod
+    def g_source_remove(source_id):
+        if source_id is not None:
+            GLib.source_remove(source_id)
+
     @staticmethod
     def addr_family_check(family, allow_af_unspec = False):
         if family == socket.AF_INET:
@@ -840,6 +845,7 @@ PRP_WIFI_AP_HW_ADDRESS  = "HwAddress"
 PRP_WIFI_AP_MODE        = "Mode"
 PRP_WIFI_AP_MAX_BITRATE = "MaxBitrate"
 PRP_WIFI_AP_STRENGTH    = "Strength"
+PRP_WIFI_AP_LAST_SEEN   = "LastSeen"
 
 class WifiAp(ExportedObj):
 
@@ -875,6 +881,7 @@ class WifiAp(ExportedObj):
             PRP_WIFI_AP_MODE:        dbus.UInt32(getattr(NM,'80211Mode').INFRA),
             PRP_WIFI_AP_MAX_BITRATE: dbus.UInt32(54000),
             PRP_WIFI_AP_STRENGTH:    dbus.Byte(strength),
+            PRP_WIFI_AP_LAST_SEEN:   dbus.Int32(NM.utils_get_timestamp_msec() / 1000),
         }
 
         self.dbus_interface_add(IFACE_WIFI_AP, props, WifiAp.PropertiesChanged)
@@ -902,6 +909,18 @@ class WifiDevice(Device):
             mac = Util.random_mac(self.ident)
 
         self.aps = []
+        self.scan_cb_id = None
+
+        # Note: we would like to simulate how nmcli calls RequestScan() and we could
+        # do so by using an older timestamp. However, that makes the client tests
+        # racy, because if a bunch of nmcli instances run in parallel against this
+        # service, earlier instances will issue a RequestScan(), while later instances
+        # won't do that (because the LastScan timestamp is already updated). That means,
+        # the later instances will print the scan result immediately, and in another sort
+        # order. That should be fixed, by nmcli not starting to print anything, before
+        # all RequestScan() requests complete, and thus, always print a consistent list
+        # of results.
+        ts = NM.utils_get_timestamp_msec()
 
         props = {
             PRP_WIFI_HW_ADDRESS:            mac,
@@ -911,7 +930,7 @@ class WifiDevice(Device):
             PRP_WIFI_WIRELESS_CAPABILITIES: dbus.UInt32(0xFF),
             PRP_WIFI_ACCESS_POINTS:         ExportedObj.to_path_array(self.aps),
             PRP_WIFI_ACTIVE_ACCESS_POINT:   ExportedObj.to_path(None),
-            PRP_WIFI_LAST_SCAN:             NM.utils_get_timestamp_msec(),
+            PRP_WIFI_LAST_SCAN:             dbus.Int64(ts),
         }
 
         self.dbus_interface_add(IFACE_WIFI, props, WifiDevice.PropertiesChanged)
@@ -928,6 +947,15 @@ class WifiDevice(Device):
 
     @dbus.service.method(dbus_interface=IFACE_WIFI, in_signature='a{sv}', out_signature='')
     def RequestScan(self, props):
+        self.scan_cb_id = Util.g_source_remove(self.scan_cb_id)
+        def cb():
+            ts = NM.utils_get_timestamp_msec()
+            for ap in self.aps:
+                ap._dbus_property_set(IFACE_WIFI_AP, PRP_WIFI_AP_LAST_SEEN, dbus.Int32(ts / 1000))
+            self._dbus_property_set(IFACE_WIFI, PRP_WIFI_LAST_SCAN, dbus.Int64(ts))
+            self.scan_cb_id = None
+            return False
+        self.scan_cb_id = GLib.idle_add(cb)
         pass
 
     @dbus.service.signal(IFACE_WIFI, signature='o')
@@ -947,6 +975,10 @@ class WifiDevice(Device):
         self.AccessPointRemoved(ExportedObj.to_path(ap))
         ap.unexport()
 
+    def stop(self):
+        self.scan_cb_id = Util.g_source_remove(self.scan_cb_id)
+        super(WifiDevice, self).stop()
+
     @dbus.service.signal(IFACE_WIFI, signature='o')
     def AccessPointRemoved(self, ap_path):
         pass
@@ -1138,11 +1170,7 @@ class ActiveConnection(ExportedObj):
         self.StateChanged(state, dbus.UInt32(reason))
 
     def activation_cancel(self):
-        if self._activation_id is None:
-            return False
-        GLib.source_remove(self._activation_id)
-        self._activation_id = None
-        return True
+        self._activation_id = Util.g_source_remove(self._activation_id)
 
     def _activation_step2(self):
         assert self._activation_id is not None