Hi Mike,
this seems to be a duplicate of
https://github.com/ArcticaProject/nx-libs/issues/161
It would be really helpful, if you could test this with a non-X2Go based NX session.
How to achieve this:
1) Adapt to your setup/needs: [1]
2) Launch VcXsrv on Windows machine
3) launch nxagent session on Linux server
4) Launch KDE4 inside the NX session
5) Launch nxproxy on the windows client as shown by [1]
6) Test if the same issue occurs as observed with X2Go Client
I seem to remember that there is some Window-size manipulation code in X2Go Client somewhere when built on MS Win, so that might be obsolete with NX 3.6.
Mike
[1] https://github.com/ArcticaProject/nx-libs/blob/3.6.x/ testscripts/run-nxproxy2nxagen t-over-network