[1.3.3389] Colonist voluntarily stands in fire to open grave

[asanbr]

I ordered a colonist to open a grave when a fire was nearby, to take advantage of the fire to burn some corpses.

To my surprise, the colonist would only stand on a specific tile to do this,  1 square down and 1 left of the grave. And on this specific tile, a fire was already burning. So he went into the fire , started digging the grave, and while doing so, caught fire and got severely hurt. This cannot be intentional behavior.