What kind of symbiosis is oxpecker bird and hippopotamus?

In the past it was believed to be Mutualism but the current standing on this issue is that they are a semi-parasitic relationship. This is because the oxpecker gets food and the hippo gets cleaned, but the oxpecker also picks at the cut to keep it open and get more food. This makes it more prone to infection and it also continues to hurt the other animal.