It is about that Eos, he's most likely lagging.
Anticipating movement is a skill thing, not a bug thing. Even with lag. That's how pretty much all internet games with fast action work... positioning is like, the key to owning.
...and yes, Resync is great. I dinstinctly remember how often I used it 10+ years ago on IPY; whether that was related to that client version, RunUO's early emulation, or just worse lag I'm not quite sure.
I also think a main culprit of Desyncs - at least back then - was rubberbanding. Like, if you ran treestump patch, you were prolly gonna desync more often than someone who didn't.