I have lost the ability to Scan Workgroup and browse the shares from the Network Neighborhood tab. I was able to do this before the latest updates.

It is not limited to Kubuntu. I am unable to Scan Workgroup in Kubuntu 12.04, Kubuntu 16.04, and Fedora 23 after taking updates.

The following updates were taken on Kubuntu 12.04:
libsmbclient
libwbclient0
optipng
samba-common
samba-common-bin
smbclient

After the updates I get the following behavior on Kubuntu 12.04:
I click on my network and I'm asked for username and password for the host
I enter my username and password and get an error that says "The list of arguments for the "net" command could not be assembled"
When I click OK i get an error that says "The list of servers could not be retrieved"
The details of this error say:
Invalid command: net
Invalid ip address specified
Could not connect to server 127.0.0.1
Conncetion failed: NT_STATUS_CONNECTION_REFUSED
xargs: /bin/bash: exited with status 255; aborting

This behavior I get on Kubuntu 16.04 and Fedora 23 is this:
I click on my network and it asks for username and password for a specific host on my network
It hangs retrieving the list of servers belonging to domain for [my network name]

I haven't found a recent bug reports for this.