While messing around with fireworks for a custom map i discovered this bug with fireworks. If you spawn fireworks with the firework item in the correct position, they can clip through blocks fully or partially.

What I expected to happen was...:
If I create a firework, for it to normally obey physics, and be, well 'blocked' by blocks.

What actually happened was...:
Sometimes, the firework would clip through a block that should block it, specifically, when spawned where two blocks diagonally meet, or near to the top of a block just under a ceiling.

Steps to Reproduce:
1. Get a firework.
2. Build an enclosed box of any block, with a 1x1x2 (XxZxY) hole in the center.
3. Go into that hole, and either look at the corner where two sides meet, and right click with the firework there, or look up at the block one under the ceiling and right click close to the top few pixels of it. Note that the firework will clip through the block partially or fully, and explode outside of the box. Note: in the corner situation, the firework of behaves glitchily inside the block, then exits it on some side, or is blocked by the side of the block and explodes inside of it. Also, this works with transparent and non-transparent blocks, the ice just made it easier to see.