Noticed that running Command 1 (below) does not update comparators next to the furnace so that they output a redstone signal. Running Command 2 (below) on a spot currently occupied by a furnace with items in it's inventory does however update a comparator and causes its output to change to no signal.
Further Clarification: Using /setblock to replace one block entity with another (given that the initial block entity had items in it and caused a comparator to output a signal) will update the comparator adjacent to the block entity, but replacing a block entity that has no inventory items (or a normal block) with a filled one will not update the comparator.
Command 1:
/setblock ~2 ~ ~ furnace 0 replace {Items:[{id:stone,Count:1,Slot:0}]}
Command 2:
/setblock ~2 ~ ~ furnace 0 replace
Related issues
Comments

Confirmed.

Is this still a concern in the current Minecraft version? If so, please update the affected versions in order to best aid Mojang ensuring bugs are still valid in the latest releases/pre-releases. If this has been done, we can reopen the issue.
Keep in mind that the "Resolved"-Status on this ticket just means "Answered", and that we are waiting for further information on whether this issue still exists or not. We will reopen it as soon as the requested information has been delivered.
Does this happen with blockdata?
Duplicate ofRelates to MC-31100