If you throw a Bottle o' Enchanting into a bubble column, while standing at the edge of the column the Bottle o' Enchanting is stuck a certain height but still under water. It stays there while bouncing up and down a bit, like items do when they are in a bubble column but at the surface.

1.15.2 and below seems not to be affected, in these versions the Bottle o' Enchanting are not even effected by the bubble column.

What I expected to happen:
I would expect it to go in the bubble column and after a while getting up to the surface. This is where i expect it to bounce. Like anvils, sand, splash potions etc. do.

What actually happened:

The Bottle o' Enchanting was stuck in a bubble column. So if you through it in a bubble column from the edge of the water, it sinks down to 3-4 blocks and stays there. It goes even deeper if you fly up a few blocks and throw from there. If you go up high of shorten your column the xp bottles break like the usually do.

While reproducing this bug I found out that the xp bottle behaves normal as you throw it down on / near the edge of two water blocks at the top of the water column.

As well it seems like the splash function of the Bottle o' Enchanting does not work while they are stuck in the water column. At least I could not get them to. (Not sure if that is a new issue, I leave it in for now.)

Steps to Reproduce:

1. Make a water column to create a bubble column with soulsand
2. Stand at the edge of the blocks that surround the bubbles and throw the Bottle o' Enchanting into the bubbles near the center of the water block
3. Then the xp bottles are stuck in the bubbles and bounce up and down a bit
4. If you throw the Bottle o' Enchanting in the bubble column at the edge of two bubble columns they behave as normal splash potions or items. So they come back to the surface. It only appears to happen while there are more than on water source block at top. It can not reproduced at a one wide bubble column. Here they behave as in step 3.