I'm not sure when this started occurring, but water doesn't seem to interact with entities. Items don't float, fish flop around while in it, players don't drown or swim, and fall damage isn't absorbed. However, water still flows and water logs as expected.

I believe the issue was caused by the water changes every couple of snapshots. I've tried to recreate this on a new world, but I'm not getting any results. Testing on older backups of the affect world, I've learned this;

Upgrading from snapshot 18w15a -> 18w19b caused water to behave, weird. Moving in water acts as air, but everything else acts normal.

Upgrading from snapshot 18w19b -> 18w20c caused water to stop interacting with fish mobs. I spawned a salmon in the water, and it suffocated as if I spawned it on dry land. However, players could drown, items floated, and the swimming sound effects played.

Finally, upgrading from snapshot 18w20c -> 18w22c complete breaks entity interaction with water. Players can't drown, items sink, no sound effects, nothing. Water now basically acts as liquid air.

Side Note: Lava is affected by this. Lava looks like water, but acts as lava in every way.

You may be able to recreate this bug by creating a super-flat world with the 'Void' prefix in snapshot 18w05a. Then slowly upgrade the world in the following order;

18w05a -> 18w07c -> 18w08b -> 18w10b -> 18w11a -> 18w14b -> 18w15a -> 18w19b -> 18w20c -> 18w22c

Once you reach 18w22c, water should be broken. I've haven't tested this to be true, but that's what I got based from my testing and log of backups.

Here are some video links demonstrating the water breaking and the lava texturing issues.

Water Interaction Broken: https://www.youtube.com/watch?v=E4w673KHlNc
Lava Textured as Water: https://www.youtube.com/watch?v=4RMQHYqICJo