Still happens as of 19w07a
this issue us not exclusive to ocean revines I noticed it's ocean wide.
i noticed that when this happens a lot to me and whenever these 2 topped kelp try to grow they have a chance to break the whole plant
and if a lot of that type of kelp generates in one area this can cause item lag in extreame cases.
I can confirm this bug and it seems that however many arrows you have in your off hand when you shot the bow is how many it will duplicate this seems to work with all of the potion arrows but the spectral arrows.
I'm having this problem to this only seems to happen if i change the mipmap setting by more then 2 and if you exit the menu and your in a world the game will freeze for a little bit then it fixes itself.
To be honest the only thing i did was leave the game open on the title screen for about a day cause i forgot i had it open. When i came back and tried useing it was useing over 10 gb of ram and riseing semi fast. Only thing that happened was my computer was in standby mode abd i woke it up I dont use any mods. What i used to measure my memory useage was windows inbult task manager and on the sevices tab i saw mincraft and when i was watching it for a min the ram number was going up at about 50-100 mb a second no clue what triggered it.