Uploaded World to Realms crashes

I have a world created on the xbox 360 works fine almost no changes, 5mb file. Upload to the Xbox One edition of Minecraft and it works fine and no issue. Then when uploaded to the Realms it will only work as long as I don't go near spawn/ loaded chunks from previous version. It starts to glitch and skip frames then I get disconnected. Sometimes I can jump on it but will get disconnected quickly. This is the same for the world on the whole 'Minecraft' version not just Realms.