I used to frequently have the same problem. Also I had a habit of actually walking into the fire when approaching a wooden cooking station.

I discovered that the grilled meat was dropping, not onto the floor, but into the fire. (So that is why I end up with coal in my fire!) This is how I fixed it.

A campfire must be built on a 2 by 2 meter square of bare ground or a 2 by 2 meter stone floor piece. Outline that 2 by 2 meter square with horizontal wood beams resting on the ground. One go right up to the fire, as long as one is not sprinting, and one will stop when one's feet strike the horizontal wood beam.

Can't set oneself on fire by walking into the fire. And one is close enough for auto-pickup to function perfectly when removing meat from the cooking station(s) on the fire.

Please note that when one progresses far enough to build an iron cooking station, one must approach it so that one is close to the center of it's 4 meter length. If one is too close to one end or the other, meat at the far end may still fall into the fire when removed.