The old issue was a bug that has been fixed meanwhile.
A good XRun example is in this post: Storing image with consistent filename - #2 by ulrich
can use a seed to generate the numbers, like testkantu.py 5 if i want the seed to be a variable can i use
“Value”: “${seed} > test.csv”?
Yes, that should work. As for why it does not work in your case, I will test it later today and update this post 