Why is svn not saving my password in Pi-OS?

This is strange to me since I have not seen it before.
I have svn installed on a newly set up RPi3 running Pi-OS (previously
named Raspbian) Linux.
I installed svn via apt.

The RPi3 has a GUI, which I can access via VNC through a VPN tunnel (I
am working remotely from home).

If I start a terminal in the GUI and navigate to the project wc dir
and then issue an svn up command a GUI dialog pops up on the side
asking me for a password. This happens every time so it seems not to
remember what I have entered.

Contrast this to when I access another *non-GUI* RPi using PuTTY.

When I use the svn up command there everything just executes as
expected and no password is requested because I entered it way back
when I checked out the wc.

Back to the new RPi3, if I access it through PuTTY instead then the
svn up command just does exactly nothing, it just sits there!
Probably it pushes a GUI login box onto the invisible GUI...

How can I configure (?) svn such that it caches the password in the
same way as it has done on all of my other RPi units before.

I need to be able to work on this device BOTH via SSH login using
PuTTY and inside the GUI when connecting via VNC.

One difference of course is that the svn client on the RPi3 is a newer
version ( 1.10.4 r1850624) than what I have used before and what is
used on the svn server (1.9.7).

Any ideas?

-- 
Bo Berglund
Developer in Sweden