I can confirm the bucket emptying of milk from buckets is still an issue as of 11/28/19.
It happens both when:
1) you quick move a bucket of milk into a chest (or ender chest; haven't tested shulkers)
2) you enter your inventory then pick up the bucket to move it from the inventory slot
If you have a stack of buckets and one pops out of your hotbar that milk is movable; it seems the only unmovable-without-emptying bucket occurs when it is on the hotbar
I've noticed if you take a quick 'sip' of milk (enough to make the sound and/or graphic effect for a moment) but stop quickly the bucket of milk stuck in the inventory will then become moveable. These buckets then act normal and can be placed in chests etc
Max George Manoles
I can confirm the bucket emptying of milk from buckets is still an issue as of 11/28/19.
It happens both when:
1) you quick move a bucket of milk into a chest (or ender chest; haven't tested shulkers)
2) you enter your inventory then pick up the bucket to move it from the inventory slot
If you have a stack of buckets and one pops out of your hotbar that milk is movable; it seems the only unmovable-without-emptying bucket occurs when it is on the hotbar
I've noticed if you take a quick 'sip' of milk (enough to make the sound and/or graphic effect for a moment) but stop quickly the bucket of milk stuck in the inventory will then become moveable. These buckets then act normal and can be placed in chests etc
(Bedrock Realm on Xbox One)