The CT ought never be mounted directly so close to a right-angle bend in the neutral bussing.
For the CT is going to be reading flux across ninety-degrees, too.
I have never seen this type of warning when applying CT's, but I have only been doing it for 35 years. CTs are regularly installed near 90° turns in bus bar and conductors.
The CT also looks like it's a total hack job. CTs are not supposed to be so over-sized.
CTs this oversized are very common for zero sequence ground fault measurements. If you look carefully you can see the back of the CT appears to extend past the rear phase bus.
More commentary is in order from the OP....
I'd shut the system down and remove this gadget immediately.
For sure.
It is hard to see, but I could be convinced this is corner grounded conductor system. It is hard to follow the bussing to the right of the CT.
