The bug
Bubble columns are not created when pouring water over magma block.
How to reproduce
Build a hole like in this image:
[media]Put water in it. Bubbles do not appear.
[media]Remove and replace the magma block. Bubbles should now appear.
[media][media]
The bubbles most lightly don't appear in pic 2 since you introduced the water after the magma block was placed. Meaning that it was first surrounded in air, which we all know if it's any of the neighboring blocks of the magma block. its registered as invalid and prevents from bubble columns from being created, which in turn lead to when you placed the water above, the values never fully updated; therefor making it appear as the magma block was still surrounded in water even when it actually wasn't.
It only works when any neighboring blocks start of as being a water source, instead of air.
But I'm sure this is currently being worked on and being fixed.
Apologies for any misunderstandings and my incapability to structure sentences in this post.