Anaglyph 3D breaks when a boat is rendered.

Reproduction

1. Kill all boats in the world (/kill @e[type=boat] (needed to have a base case))
2. Enable anaglyph 3D in video settings
3. Place some water sources and slime blocks in front of you.
4. In front of the slime blocks, put glass.
5. Look at the glass.
6. Place a boat.
7. Observe that the slime blocks and water sources appear to have shifted
8. Observe that the glass is partially not rendering
9. Observe that your held item is rendered solidly several times
10. Observe that the hitbox for blocks renders black twice.

Cause

My guess is that this is caused by the invisible transparent layer that boats use to not have water inside. However, I haven't confirmed this.

Notes

All visual artifacting happens only on the blue side. The red side is more or less unaffected. As such, if you have red/blue 3D glasses, the effects can clearly be replicated by closing the red eye and only looking through the blue eye.

I can't quite classify how the artifacting works, but it might be that the red layer is less transparent when it happens.

Boats also change the way the glowing effect incorrectly behaves (see MC-111101), but that's its own issue.

Screenshots

• Items: Without boat | With boat
• Blocks shifting: Without boat | With boat
• Blocks getting cut off: Without boat | With boat
• Hitboxes drawing dark twice: Without boat | With boat