The bug
Arrows cannot pass through a non "tall-state" wall (specifically a cobblestone wall, or sandstone wall that does not have its above space filled). Versions prior to 1.16.2 Pre-Release 1 allow most projectiles to pass through the gap, but since 19w03c, only the arrow is negated.
Video Example (outdated):
Linked issues
relates to 1
Comments 4
This issue has become much less noticeable as of 20w06a.
Now, arrows cannot pass through a non "tall-state" wall (specifically a cobblestone wall, or sandstone wall that does not have its above space filled). However, other projectiles such as snowballs, ender pearls, and eggs can pass through this space.
The video is now a representation of using commands to replicate the issue.
Due to the change in how walls work in 1.16, non "tall-state" walls with blocks above them require even more specific circumstances to appear, therefor reducing the already very low effects of this issue.
In 1.16.2 Pre-Release 1, potentially due to MC-73884 getting fixed, projectiles do not pass through the gap above walls either. This not only means that the video is 100% outdated (like it was already when showing walls placed on walls without the "tall-state" present), but it also means that the only way to tell that there's a problem is to use previous versions of the game.
I'll continue updating this ticket for now.
Relates to MC-142772.