command like "/execute store result entity @e[type=cow,limit=1] Pos[1] double 10 run scoreboard players get zsm_3fps test" could work when zsm_3fps has a score of the scoreboard test, but "/execute store result entity @e[type=cow,limit=1] Motion[1] double 10 run scoreboard players get zsm_3fps test" could not work.
1.summon a cow
2. creat a scoreboard called "test"
3./scoreboard players set @p test 10
4.try this "/execute store result entity @e[type=cow,limit=1] Pos[1] double 10 run scoreboard players get @p test" and this "/execute store result entity @e[type=cow,limit=1] Motion[1] double 10 run scoreboard players get @p test", see if they works.
You're storing an extremely large value of
10 * 10 = 100, which exceeds the game's limits for motion, which is±10. This causes it to be reset to zero.