Mangrove roots don't burn in the furnace

From MCPE-161495
The mangrove roots can be burned and destroyed directly, but cannot be used as a fuel source. This is also not parity with Java, which allows the mangrove roots to be used as fuel sources.

How to Reproduce
1. Get furnace/blast furnace/smoker.
2. Smelt or cook anything with mangrove roots as the fuel source.

Observed Result
Mangrove Roots cannot be put into the fuel slot.

Expected Result
Mangrove Roots can be put into the fuel slot.

Original Description
Roots burns as a block, but not in the furnace. It's not logical. It's not logical. More that in previous previews it worked