After the update to Minecraft Bedrock Edition version 26.0.9, entities standing at the edge of a lava source (where the lava block meets a non-lava block) are incorrectly receiving only 1 point of fire damage per tick instead of the intended 4 points of lava contact damage. This regression was introduced by a code rollback intended to fix redstone mechanism issues related to MCPE-234749. In the previous version, 26.0.8, entities correctly took 4 damage per tick when in contact with the edge of a lava block.
How to Reproduce:
Place a slab and add water to it, creating a waterlogged slab.
Surround the area with glass blocks to contain the water and improve visibility.
Place a bucket of lava on top of the waterlogged slab.
Use a guardian spawn egg to spawn a guardian into the lava at the edge where it meets the waterlogged slab/glass.
Observe the damage numbers taken by the guardian (using a health display resource pack for clarity, as shown in the reference video).
Observed Result:
In version 26.0.9, the guardian takes damage very slowly, losing health at a rate consistent with receiving only 1 point of fire damage per tick. It survives significantly longer compared to its behavior in version 26.0.8.
Expected Result:
The guardian should rapidly lose health and die quickly, as it did in version 26.0.8, due to taking the full 4 points of lava contact damage per tick when touching the edge of the lava source.
This behavior is the same in the current release, 1.21.132 Hotfix, so I think it is incorrect to suggest that this is related to the fix for (MCPE-234749). Rather, it occurs in this specific setup because the guardian’s body is more in water than in lava. It does not occur with husks, for example. The guardian is 0.85 high, so it is 0.5 in water and 0.35 in lava.
In fact, this behavior was already described in (MCPE-183531).
Do you have a video of this behavior being different in 26.0.8 Preview?