The Bug:

minecraft.used:minecraft.powder_snow_bucket doesn't increase when filling a cauldron with a powder snow bucket.

Steps to Reproduce:

• Create a scoreboard objective for tracking the use of a powder snow bucket and set it to display on the sidebar.

/scoreboard objectives add UseSnowBucket minecraft.used:minecraft.powder_snow_bucket
/scoreboard objectives setdisplay sidebar UseSnowBucket

• Fill a cauldron with some powder snow using a powder snow bucket.
  →  Notice how the scoreboard doesn't increase.