The bug

When teleporting a fishing bobber, their position seemingly updates correctly, but visually they maintain their previous position. This can potentially lead to large desyncs in where the player sees the bobber and where the server thinks the bobber is. 

How to reproduce

1. Give yourself a fishing rod
2. Cast the fishing rod and let the bobber land 
3. Type 

   /execute as @e[type=minecraft:fishing_bobber] at @s run tp ~15 ~ ~

4. Then type

   /tp @s @e[type=fishing_bobber,limit=1]

   →  If done correctly, the player will be teleported a significant distance away from where the bobber appears to be.