It happens in both. First time i fell through the world into the void and rejoined the world in 1.14. I found myself without a boat in the middle of the ocean without a boat so i ragequitted. Today i found out that they fixed inconsistent chunk loading issue, so i updated my world to 1.14.1 Pre-Release 1 but it happened to me again twice. It works just fine without a map in the hand
Yeah, probably. I think generating maps just amplifies the effect and makes it more noticeable