The bug
Use a bow and crossbow attack invulnerable entity(non-biological), makes arrow become invisible.
Save and open the world again can return to normal.
You still can pick up the arrows.
Entity type: (Invulnerable:1b)
End crystal
Painting
Item frame
Glow item frame
Lead
All Boat
All minecart
All boat with chest
Bamboo raft
Bamboo raft with chest
Fireball
Arrow type:
Arrow
Tipped arrow
Spectral arrow
Fire arrow
Code analysis
Code analysis by @unknown can be found in this issue.
Linked issues
is duplicated by 1
relates to 1
Attachments
Comments 8

Can confirm in 21w03a.
Can confirm in 21w05a.
Can confirm in 21w05b.
Can confirm in 21w06a.
Video attached.
Can confirm in 21w07a.
As a note to this issue, I've left a very detailed and thurough code analysis and possible fix for this issue in MC-129934
It provides the following behavior:
[media]
Also affects the players in the creative mode in multiplayer