I've always moved the dust seal out of the way if possible (which has been every time). They are usually tapped in and not glued. Just a thin smooth edge (putty knife) to see if it can be pryed loose then slid up the tube. This will aslo let you soak up the oil that is laying between the seal and dust shield. Otherwise, even if you clean and stop the leak, you may have oil residue seeping for a while and not realize you corrected it.
Perhaps in the resting position there is a bug or blemish on the forks? When you clean them, lift the front wheel off the ground with a jack so you can see as much of the fork tube as possible.
