When a water bucket is emptied into a lava cauldron, a loud hissing sound plays, smoke is generated and an empty cauldron results. The same happens for when lava is emptied into a water cauldron.
According to the resolution of MC-204118, the fact that this behaviour does not occur in Java Edition is intended, resulting in Bedrock Edition being at fault for having it.
(I am reporting this as a parity issue as despite the fact that this behaviour has existed in Bedrock Edition for several updates, it was only added to Java Edition in the last snapshot, making it a valid parity issue.)
Linked issues
Comments 3
This does not meet the parity issue criteria that the parity difference was introduced post-Buzzy Bees update, because the disparity is as old as lava cauldrons in Bedrock. Furthermore WAI resolution on the Java tickets was based on how pouring water on a lava block in Java has always behaved, and that has never been on par with Bedrock lava cauldrons.
I am not convinced that the resolution of MC-204118 is correct. It appears to be based simply on the resolution on MC-203629, which in turn appears to be based simply on the resolution of MC-8930, which has nothing to do with cauldron behavior. I can hardly believe that a longstanding feature in Bedrock is suddenly a bug because it was not added in the first Java snapshot to introduce the block on which it is based.