PC / Xbox Series S / Nintendo Switch Cross platform gameplay glitches

I've recently set up a 10 player realm for myself and my extended family to play on across multiple platforms.  I seem to be able to play fine via both my PC and Switch, until this latest update, now I can only play on Switch. 

One of my family members on their Xbox series S has had a variety of issues as they log into the realm. 

 

What I expected to happen was...:

We can both log into the realm from our respective devices and play as normal

What actually happened was...:{}

Sometimes they log in and all they see is the blue sky and no blocks, or a limited view of their current chunk.

There seems to be a 2-3 minute delay for any block interaction or movement. I.e, player on xbox breaks a block but it doesn't break for me on PC / switch for 2-3 minutes, same with any pvp punching interactions etc. From my perspective this players ,movement is very choppy as well, however all they see is movement and block interactions as expected within the chunk that actually loads for them. Neither of us have done any messing with graphical setting or anything, I believe all our rendering distances etc have been left as the default.

 

Steps to Reproduce:
1.  Player 1 / realm owner log in to realm on desired platform - everything should load in
2. ... player 2 attempt to log in to realm on xbox series s
3. ... player 1 sees player 2 in the world. player 2 is frozen for the first 2-3 mins and then movement is choppy and any block breaking is delayed.