We are seeing some vote manipulation

We had a couple of reports today of vote manipulation happening in the Australia community. After investigating, I'm seeing a trend:

https://aussie.zone/post/21203876
https://aussie.zone/post/21124048
https://aussie.zone/post/21194319
https://aussie.zone/post/21130833

The votes in all these posts look like this. In this example, only two of the downvotes look legitimate. The rest are coming from three instances that don't appear to be real Lemmy sites. One of them doesn't even resolve.