The Bug:
Parrots lose their scoreboard scores when mounting players' shoulders.
Steps to Reproduce:
Create a dummy scoreboard objective and set it to display on the sidebar by using the commands provided below.
/scoreboard objectives add test dummy
/scoreboard objectives setdisplay sidebar test
Summon a parrot and give it a score of 1 by using the command provided below.
/scoreboard players add @e[type=minecraft:parrot,sort=nearest,limit=1] test 1
Tame the parrot and get it to mount your shoulder.
Take note as to whether or not parrots lose their scoreboard scores when mounting players' shoulders.
Observed Behavior:
Parrots lose their scoreboard scores.
Expected Behavior:
Parrots would not lose their scoreboard scores.
Can confirm in 21w11a.