Problem when creating a function from two splines

[r1xn]

Hi everyone,
I am facing a issue in CATIA when trying to create a function from two splines:

I have two existing splines and when i try to create a function e.g., using "Combine" the result is automatically named "curve" instead of the operator (see the attachment). The curve is non-editable, i cannot modify its parameters (for example minimizing the distance between the combination and object) and I've also tried reinstalling CATIA. I'm currently running on CATIAV5-6R2024.
Has anyone encountered this and knows ho to fix it?

Thanks in advance for any tips!