Gary Illyes from Google in his Reddit AMA said that Google does not have an internal linking over optimization penalty. He went on to say, in his Gary tone, “you can abuse your internal links as much as you want AFAIK.”
Here was the question:
Straightforward question: is there an internal linking overoptimization penalty?
I’m not talking about keyword stuffing the anchor text, but using a relevant anchor repeatedly and adding internal links from relevant pages in batches (dozens at the same time) to a specific page.
Is it possible that this is interpreted by Google as manipulative, even if it’s internal linking?
Here is Gary’s answer:
No, you can abuse your internal links as much as you want AFAIK.
Matt Cutts said something very similar back in 2013, John Mueller confirmed internal links are different but also said internal links anchor text does matter.
Forum discussion at Reddit.