[MC-166272] Comparator can't read inventory of campfire

Unlike all the other blocks with inventory - with NBT {Items[]} - the comparator cannot read the inventory of a campfire.
I believe this may be a significant problem of inconsistency.

What I expected to happen was...:
I expected the Comparator can read all the inventories.

What actually happened was...:
The Comparator can read all the inventories, but not the Campfire. I doubt that this is intended behaviour.

Steps to Reproduce:
1. Place Campfire and a Comparator reading it
2. Right click on the Campfire with raw food

3. Witness the result: the comparator doen't lit

Possible solution:

Campfire Block Status	N. of Items	Output of Comparator
lit=false, signal_fire=false	0	0
lit=false, signal_fire=true	0	1
lit=true, signal_fire=false	0	1
lit=true, signal_fire=true	0	2
lit=false, signal_fire=false	1	3
lit=false, signal_fire=true	1	4
lit=true, signal_fire=false	1	4
lit=true, signal_fire=true	1	5
lit=false, signal_fire=false	2	6
lit=false, signal_fire=true	2	7
lit=true, signal_fire=false	2	7
lit=true, signal_fire=true	2	8
lit=false, signal_fire=false	3	9
lit=false, signal_fire=true	3	10
lit=true, signal_fire=false	3	10
lit=true, signal_fire=true	3	11
lit=false, signal_fire=false	4	12
lit=false, signal_fire=true	4	13
lit=true, signal_fire=false	4	13
lit=true, signal_fire=true	4	14

N = N. of Items
L = int( lit==true )
S = int( signal_fire==true )

OUTPUT = N*3 + L + S