sounds like a coincidence to me unless something got disturbed in the
humidifier. You may have dislodged a piece of scale from inside the pipe that
has rendered your inlet valve of the humifier imoperable. YOur placement of
the piercing valve would have nothing to do with the leak unless water is
following the tube down below the humidifier making you think that the leak is
there and not up at the connection at the copper. Ck it out carefully to find
exactly where the water is coming from. If it is the inlet valve you may be
able to clean it.