Unless it has been leaking all along and all that is being seen is the flowing wellhead pressure. Entirely possible.
The pressure would rise until the fracture gradient at the leak is reached and the flow reaches steady state at the back pressure of the fracture gradient. If the leak point is low enough this will persist until the zone that is accepting the leak becomes charged with oil and gas, the pressure exceeds the fracture / overburden pressure and a broach cascades to the surface or the next zone further up in the strata. Saw it in the South China Sea... on another BP disaster that never got any press because it was all gas.
That is a possibility. The seep was just a natural one. Been then before they started drilling even. But what are the odds ? Any geologists what to comment ? Perhaps to accurately determine the odds we need the precise distance between Maconda and seep.