I'm trying to browse lemmy.world from another instance to reduce load, but it's a completely different experience?

Any post in a lemmy.world community I view from another instance (e.g. programming.dev) shows different content than when viewing from lemmy.world directly. Many comments are missing. There seems to be a massive lag, sometimes more than 1 day. Are instances really that far out of sync? It's hard to contribute from another instance knowing that nobody will see my comments for ~days