Cauldron deletes overstacked tinted shulker boxes

When cleaning shulker boxes that are in a stack greater than 1, cauldron deletes the entire stack. 
Steps to reproduce: 

1. run the command:
/give @s minecraft:white_shulker_box[minecraft:max_stack_size=64] 64
2. place a cauldron with water:
/setblock ~ ~ ~ minecraft:water_cauldron
3. Try cleaning the shulker boxes, and observe that only 1 shulker box is cleaned, replacing the other 63.

Expected behavior:
the cleaned shulkerbox should be added in a differnt inventory space, instead of replacing the entire stack