Ashient debrish can generate exposed to fire or lava

When I extinguished fire over to my beta test survival world, I was suprised to see a piece of debrish! After some testing I manage to locate more debrish exposed to lava on lava lakes or fire

Steps to Reproduce:

 

1. It's pure luck if you find debrish under fire (red, not soul)
2. You can drain lava lakes to find debrish with a fill command

Observed Results:
Debrish generates under lava or fire

Expected Results:
Debrish should only generate covered with netherrack, or other full blocks and not that close to surface

Screenshots/Videos attached: Yes, not very conviencing tho as the fire has been extinguished.