Lava with block on top does not cause fire damage to entities.

Summary:
When there is a block on top of lava, entities like chicken or sheep, do not take fire damage from the lava, they do suffocate in the lava. Removing the block above the lava causes the lava to do fire damage again. This issue also breaks some chicken farm/cooker designs.

Steps to reproduce (example):
1. Place a adult chicken on a bottom half slab in a enclosure.
2. Place lava on top of the half slab using a dispenser.
3. Now place a block on top of the lava
4. Notice the chicken doesn't take fire damage from the lava and the dropped item is not cooked. It dies from suffocation damage.

Use the attached world (1.2.13.6) to see some examples. MCPE-31481.mcworld

Video:
MCPE-31481.mp4

What i expected to happen:
The entity (like chicken or sheep) to take fire damage and drop cooked items and not only take suffocation damage while in the lava (with a block on top).