Issue With Rendering Chunks

Whenever I fast fly over my Main City, I experience a Slow Chunk Rendering Issue. It takes 30 seconds for the chunks to finally render back into place, and I feel like it's now just a big waiting game. This issue does not occur outside my city, but I still think it's a bug because I have not experienced any drop frames within the situation.

It's a shame because I real like this new Better Together Version for what it offers, and I keep having to stop my self going back to the 4J Edition

 

Kind Regards.

The Terrari