Question about Parallelism in Correlative Conjunctions

Hi, I have a quick question about whether parallelism has been correctly used here or not:

Research has shown that people who consume meat have higher rates of disorders due to cholesterol, which not only contributes to heart disease but also diabetes, high blood pressure and a host of other problems, whereas plant-based foods have been shown to alleviate such disorders.

I guess that technically speaking, the correct use should look like this:

"...which not only contributes to heart disease but also contributes to diabetes, ..."

or, alternatively, it should probably look like this:

"...which contributes not only to heart disease but also to diabetes, ..."

You see, even though the two options I've listed above are grammatically correct, I feel that the original use (quoted at the top of this post) sounds natural and correct. Is it in fact correct? If so, then due to what rule? Or is it grammatically incorrect?

Thank you so much! Would greatly appreciate your insight. Cheers