Secrets request error: No agents were available for this request

I'm using Kubuntu cosmic on a Dell Precision 5520, this is the list of versions:

ii  network-manager                               1.12.4-1ubuntu1.2
ii  network-manager-gnome                         1.8.18-2ubuntu2  
ii  network-manager-openconnect                   1.2.4-1.1        
ii  network-manager-openconnect-gnome             1.2.4-1.1        
ii  network-manager-openvpn                       1.8.6-1ubuntu1   
ii  network-manager-openvpn-gnome                 1.8.6-1ubuntu1   
ii  network-manager-vpnc                          1.2.6-1          

I have two issues that might be related. First, from time to time, a new connection for a network I already used appears on the list. I found that in fact, there are new files in /etc/NetworkManager/system-connections/:

-rw------- 1 root root  353 Aug 13  2018  WIFI_Network
-rw------- 1 root root  353 Mar 15 14:47  WIFI_Network-6b12f9ec-5192-43c6-93fe-3483188b7957
-rw------- 1 root root  353 Mar 15 13:47  WIFI_Network-e59ef0ca-b7ca-408a-b954-cfc872acbd6a

The only difference I find in those files are the UUIDs:

$ sudo diff -u /etc/NetworkManager/system-connections/WIFI_Network /etc/NetworkManager/system-connections/WIFI_Network-6b12f9ec-5192-43c6-93fe-3483188b7957 
--- /etc/NetworkManager/system-connections/WIFI_Network    2018-08-13 23:23:59.915045200 +0200
+++ /etc/NetworkManager/system-connections/Invitados-6b12f9ec-5192-43c6-93fe-3483188b7957       2019-03-15 14:47:06.037622154 +0100
@@ -1,6 +1,6 @@
 [connection]
 id=WIFI_Network
-uuid=4c16e4b0-1a1d-43a5-932a-f34530985742
+uuid=6b12f9ec-5192-43c6-93fe-3483188b7957
 type=wifi
 permissions=user:mdione:;
 

The second issue is that when I try to connect to one of those n-plicated networks, NM just don't and I get no UI feedback about it. I stopped the daemon and restarted with --debug. You'll find a full log attached.

NM-bug.log

The relevant lines I think are:

<debug> [1552657626.0293] settings-connection[0x564a81f5a0b0,6b12f9ec-5192-43c6-93fe-3483188b7957]: failed to read connection timestamp: Key file does not have key “6b12f9ec-5192-43c6-93fe-3483188b7957” in group “timestamps”
<debug> [1552657626.0337] ++ connection 'new connection' (0x564a81f5a0b0/NMSKeyfileConnection/"802-11-wireless"): [/org/freedesktop/NetworkManager/Settings/23]
<debug> [1552657626.0339] ++ connection.id             = 'WIFI_Network'
<debug> [1552657626.0340] ++ connection.uuid           = '6b12f9ec-5192-43c6-93fe-3483188b7957'
<info>  [1552657626.0459] settings-connection[0x564a81f5a0b0,6b12f9ec-5192-43c6-93fe-3483188b7957]: write: successfully updated (keyfile: update /etc/NetworkManager/system-connections/WIFI_Network-6b12f9ec-5192-43c6-93fe-3483188b7957 (6b12f9ec-5192-43c6-93fe-3483188b7957,"WIFI_Network") and persist connection), connection was modified in the process
<debug> [1552657626.0735] settings-connection[0x564a81f5a0b0,6b12f9ec-5192-43c6-93fe-3483188b7957]: (802-11-wireless-security:0x564a81f0be80) secrets request error: No agents were available for this request.

Any ideas what could be wrong?