Summary:
Before 20w45a washing a banner in cauldron did not reduce the water level in creative mode, which was intentional per MC-63058. Now it reduces the water level even in creative mode.
Steps to reproduce:
Change your gamemode to Creative.
/gamemode creative
Place a cauldron with water.
/setblock ~1 ~ ~ water_cauldron[level=3]
Right click the cauldron with banner.
/give @p minecraft:white_banner[banner_patterns=[{"pattern":"minecraft:cross","color":"pink"}]]
→ ❌ Water level of the cauldron was lowered
Linked issues
relates to 2
Comments

Thank you for your report!
After consideration, the issue is being closed as Working as Intended.
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