This has been covered in the Known Issues post sticky at top of the forum:
Random is random. Sometimes that will happen, but not always. It happens to me sometime too, but not often.
It will happen more often sub-70 because each item has a minimum drop level. At low levels, the possible items are limited and therefore you will see the same items appear more often.
As I said, “random” (RNG) is just a simple maths function. It doesn’t know what it is generated for, kadala/primal/reforge/…, It doesn’t care.