Visual issues new to a20, not affecting others in server

[Thewanderingone]

Hello all,

Since updating our server to a20 I have noticed a strange visual bug that makes it look like I am in a moving "land bowl". I have a youtube like to help show what I am seeing. Not sure where to start with this issue. 
 

Any and all help is appreciated!

 

[Beelzybub]

Looks like an old world was used. And mods. Clean your old data from the server and the client.