World crashes after about 2-3 minutes after being loaded while moving.  World size is 11.8MB and seed is -1890628709.  Caves & Cliffs Experimental mode is activated.  World was created in 1.17.0.56, upgraded to .58 and then .10.20.  I made a copy of the world and set it to creative and peaceful.  Sitting still in creative for 5 minutes with no crash, however game crashed within 2 minutes of when I started moving around.  World size has increased to 13.9mb while moving around in already generated areas and crashing repeatedly.  Peaceful mode does not appear to extend the time before a crash happens.