Ive got this issue except converting chunks seem to rise upwards while the rest of the world remains on the same level, The lower chunk water level of rivers and whatnot is 62 while the water level of the Upper chunks is 126
I would like to add that while it is cool It is going to cause issues for me in the future as its moved places I have built upwards luckily left the main place free of the wacky terrain generation.
One of my older Resource packs uploaded for testing. Produces same unsolvable effect