For the example you give you are right the answer is 1.
I think that, one way or another, you modify the input array hence the reference solution didn't get the same input as yours.

In the tests I modified the evaluation order of the reference solution and of your solution so your solution doesn't longer influence the reference solution. Please tell me if you succeed now.

BTW note that 51 people passed the C kata.

Having issues with my C solution:
for the array 323064,48424,89607,323456,90020,322992,322875,52578,322740,323200,22530,82622 and K=7 i get Expected 0, got 1.
BUT 322992,322875 are consecutive and for both K=7.
Also checked in an online calculator to make sure I got the right K calculated (https://www.calculatorsoup.com/calculators/math/prime-factors.php)
Any help will be appreciated =]