I'm having an issue connecting with my NAS on the Plasma laptop. When I rebooted after installing the update, I next invoked a mount -a to connect with all the NAS shares, and got an error telling me that "server DiskStation415 not found." Could be a DNS problem of some kind?
To find out whether the NAS was okay without running upstairs to check it, I tried accessing it with my travel laptop, which hadn't been updated yet, and there was no problem. Plasma is the DE on the laptop that failed and the travel laptop that hadn't been updated, so the problem appears to be update-related.
To determine whether it was a KDE issue, I next tested the Xfce laptop (which had also been updated). There was no problem with the Xfce laptop. the mount -a command completed successfully, and I was able to access my ISOs share when I tried. So, this appears to be an updated-related problem that affects only Plasma.
EDIT: On the Plasma laptop where I discovered this problem, I launched a Budgie VM. I was able to connect with the NAS without an issue, and access one of its shares. So no problem there.