Place an end crystal adjacent to a wall of glass panes or iron bars. Shoot the crystal through the bars or glass. The crystal will explode, even though it appears to be protected by the glass. This does not appear to work with melee weapons, so it is assumed to be a bug.

This may happen because arrow tips pierce slightly into the surface of blocks they hit. It would be most easily fixed by making the End Crystal hitbox slightly smaller.

This needs to be fixed because players may want to use end crystals surrounded by glass panes or iron bars as safe decorations. If a stray arrow strikes the "display case" the player's creation will be destroyed, and this does not make sense.