blocks that can contain water have to be waterlogged. flowing water from will not waterlog the block. try filling your lake (or whatever) from the bottom up by making source blocks on each level until it is full.
This is not a bug. this is how water has always worked.
The "water flow problem" on the surface is because water sources cannot form without something underneath them. Water sources will form if there is another source block of water below where it should form, or if there is a block below where it should form.
blocks that can contain water have to be waterlogged. flowing water from will not waterlog the block. try filling your lake (or whatever) from the bottom up by making source blocks on each level until it is full.
This is not a bug. this is how water has always worked.
The "water flow problem" on the surface is because water sources cannot form without something underneath them. Water sources will form if there is another source block of water below where it should form, or if there is a block below where it should form.