Friends having issues on realm - have to be added each time, cant use things, dont get bricks, etc

As the realm owner i am having no problems at all accessing the game or during game play. However the other 2 players who are connecting to the realm to play are having lots of issues. One of the machines is a high end gaming alienware running windows 10 (Saviux) and the other is an acer running windows 7 (LucyTheBold) that is an exact duplicate of mine (akralia) since I maintain both of the acers.

It started with Lucy having to be invited every single time she would log out instead of being white listed and being able to connect at any time. Saviux got whitelisted for a while but has recently run into an issue where he has to have an invite each time now. In the last week or so they have now repeatedly experienced an issue where they cant interact with the world - they break bricks but dont get them in their inventory, they cant open doors or use chests or pick things up or place bricks or anything. I sit side by side with Lucy and I an see on my screen her character has the item in her hand or is at the door / chest and it opens and shuts immediately while on her screen it appears she has nothing in her hand or the door just doesnt do anything. Saviux has started having an issue where he gets disconnected about 20-25 times in the space of 30 minutes.

We have tried updating all the software and java, ensured minecraft is whitelisted in the firewall and antivirus. I have closed the world and reopened it but cant get it to stop bugging out The only difference in the realm between mine and Lucy that I can tell is that I am the realm owner and she is not.

This seems like a realms issue since it is only affecting 1 of 2 identical computers on the same network and is affecting a computer using a completely different setup and operating system at a different location

Please advise on what I can do to help resolve this issue as it isnt any fun to play while encountering these issues