My friend recently started a Realms trial, but playing on that particular world has been difficult due to increasing lag and sporadic disconnects. The lag gets such that world updates appear to roll themselves back right after they happen, and DCs are such that we either can't reconnect for a few minutes afterwards, or are able to reconnect and die instantly/are reverted back to a position we were at up to a minute before the disconnect.

Disconnections throw a generic "Disconnected from server" message and subsequent unsuccessful connection attempts are met with "Unable to connect to realm."

Per the advice of Mojang's support on Twitter, we tested with another realm and didn't encounter the sporadic DCs but did notice lag getting worse the longer we stayed connected. Support then recommended I file a bug.

We've both kept our Realms' worlds intact in case anybody would like to take a look at the data. I can provide our account names on request. Any assistance would be greatly appreciated.