Sorry for the third post in a row, but I can't edit my previous post.
So I did some more tinkering and it turns out some settings in my user.setting file cause the mod to crash the game in Novigrad (test area was around the Chameleon/Rosemary & Thyme).
The settings in question are:
In their default "ultra" setting they cause no problems, however after tweaking them, the crashes occured.
CascadeShadowDistanceScale0=3 ==> no crash
CascadeShadowDistanceScale1=3/2.5/2 ==> crash; 1.5 ==> no crash
CascadeShadowDistanceScale2=2.5/2.0 ==> crash; default value ==> no crash
CascadeShadowDistanceScale3=2 ==> crash; default value ==> no crash
I did not try every possible combination but always used the highest working value of the previous setting with the next. So my currently working settings look like this:
I hope this helps!