So this just recently started happening..

If I want to connect to one of the VPNs in my list I click on the networks icon in the tray, and select the VPN I need and click connect.

This brings up the openconnect connection information where I would normally click login. Except I can't click on anything, or even close the window. The VPN goes for a while saying 'Needs authorization', and will eventually timeout and fail to connect to the VPN. Meanwhile I now have the VPN settings window open on the screen, and it can't be closed, no buttons can be clicked, and I can't input text into any field. But I can move the window wherever.

If I try to create a new connection, something similar happens. In the initial dialog I can fill out my vpn gateway, but when I connect to it, the same sequence of events happens, I can never type in credentials or anything.

This severely hampers my ability to work.

$ yaourt -Qs plasma-nm
extra/plasma-nm 5.2.0-1 (plasma)
Plasma applet written in QML for managing network connections
$ yaourt -Qs openconnect
extra/networkmanager-openconnect 1.0.0-1
NetworkManager VPN integration for openconnect
extra/openconnect 1:7.03-1
Open client for Cisco AnyConnect VPN

This was working the last time I worked with VPN which would have been about 2 weeks ago.

Checked your pacnew files?

I have exactly the same issue. Have you been able to resolve this?

No, I haven't been able to fix this yet. I checked pacnew files, and the only two I have are locale.gen.pacnew and mirrorlist.pacnew

It is fixed in Plasma 5.2.1, now available in arch repos.