The Riptide Enchantment Can still hit entities through blocks.

Here are 2 Ways to Reproduce the Bug

Method 1:

1. Prepare a 2x2 area
2. Place a block(Preferably Glass) in the ++Quadrant of the area and the – – Quadrant of the area
3. Extend the Blocks by 2 blocks
4. Place an entity in the + - Quadrant(Preferably Armor Stands) and Place water at the - + Quadrant
5. Grab a Riptide Enchanted Trident
6. Push the Armor Stand towards the corner for it to work more accurately
7. Go to the water and stand at the corner.
8. Use the Riptide Enchantment

Method 2:

1. Place a Block 2 blocks above the Ground
2. Place an Entity at the top of the Block
3. Place water below the Block(Preferably have a 1 block gap between The block and water
4. Grab a Riptide Enchanted Trident
5. Go to the water 
6. Use the Riptide Enchantment

Expected Results from the 2 methods: Nothing Will happen, The Trident will work normally

Observed Results from the 2 methods: The Entity will get hit by the Trident