One might even make the argument that toroids, being on the outside, should not effect the impedance at all, unless the shielding was dysfunctional. (in some way)
I actually have some clip on toroids that I leave on my nanovna2's test leads all the time, to decouple the leads from the shields. I dont see any reason to not do that, and several reasons to do it.
I mostly do it because of high RF noise in my area.
Sometimes I squeeze coax between my fingers (not too hard) i order to "see" if I can locate where a fault is by the changed point. But that doesn't always work.