Scally et al shows that 30% of the gorilla genome exhibits incomplete lineage sorting with the human genome and chimpanzee genome, with 15% of the gorilla genome being closer to human than to chimpanzee, and vice versa.

That the amount of lineage sorting we see where gorillas and humans are closest together is the same as the amount where gorillas and chimpanzees are closest to each other, is exactly what would be expected from Thus there is no evidence of an excess of sharing between humans and gorillas, which is what one would expect if there had been any appreciable interbreeding between the two lineages.

The incomplete lineage sorting (ILS) that Scally observes, is not from 11 million years ago, as that does not even add up darwinistically, there can not be ILS 5 million years after human-chimpanzee and gorilla separated as the gene pool had sorted itself out at that point. Rather, the ILS is from the interbreeding event 6 million years ago (Popadin et al, 2017), at the point where the human and chimpanzee lineages speciated.

References

Mitochondrial pseudogenes suggest repeated inter-species hybridization among direct human ancestors (2017)

Insights into hominid evolution from the gorilla genome sequence (2012)