Since updating my world to this snapshot, I started to notice in my ice farming fields that ice blocks formed primarily in strips oriented east-to-west (along the x-axis), as well as a general drop in the rate that ice forms in them. Upon further inspection, I found that nearly all of the strips that ice did form in did so on blocks with even-numbered z-coordinates, such that the strips of water left liquid were odd. All of the water blocks in the farm that are supposed to freeze are otherwise eligible i.e in a snowy biome, exposed to sky, block light level not too high, and the farm had functioned as intended until updating to the latest 1.16 snapshot. This led me to believe that the changes in the latest snapshot had introduced a bug affecting selection of blocks for random ticking. However, upon further testing with other mechanics governed by block ticks, namely crop growth and redstone ore activation, it appears that not all block ticking mechanics have been affected. The world I have experienced this issue in was created in 1.14, but the area that I had built the ice farm in hadn't been generated until 1.15.2, IIRC.