When sharing on Sync, it always shares a link to whatever instance the community is on, or sometimes even the instance your home instance federated the post from, meaning I can be looking at a post from lemmy.world, from my home instance of lemmy.ca, and the share link will be from yiffit.net.
Is there a way to always share a post as coming from your home instance?
How would that work? The post exists on that instance. You’re home instance just caches a copy. To share from your home instance the post would need to be recreated on that instance, so a new community with the same name would need to be created with it.
Yes, you are viewing the post that was made on Lemmy.ca, federation allows you to see posts on other instances. You are able to see the post and comment because of federation, lemmy.world grabs a cached copy to show it’s users, the actual post is still on the original server. If you want to share a post, and let others interact in the comments, the link needs to be to the actual post. If you just want them to see something, and not know where it came from, a screenshot might be better.