Summary
Snow layers can be "waterlogged" by doing /setblock or /fill inside water.
Steps to Reproduce:
Stand in a water source block.
/setblock ~ ~ ~ snow_layer(any height will do)
You can also repeat the above with /fill.
Observed Results:
A snow layer will be placed in the water, making it "waterlogged".
Additionally,
The snow layer block can be made taller by placing more snow layers on it, without affecting its "waterlogged" status.
A "full" snow layer block placed in this manner (either setblock or adding more layers) can continue to have water flowing out.
Expected Results:
The water should disappear and the snow layer should be placed (and washed away if there are adjacent water blocks that can do so).
Affects 1.19.22