There are 2 bugs with the fireplace inside a house.
First, when you make a fireplace with stick and bark, it auto puts bark for kindling. But, when you place it from hands to fireplace inside house, it removes the bark.
Second bug. When fireplace is placed, it has 1 stick, if you take a stack of 5 sticks and try to swap the 1 inside the fireplace for the 5 in your hands/inventory, the entire fireplace disappears and you can't interact with it at all. HOWEVER, this also makes that fireplace useless until the next server reboot as you can't place another on there. The server side thinks there is already one there I assume?
Anywho, just something to note to fix. Probably already reported but what could it hurt in case you didn't know.