[GMS] MagicsBOW was lucky and found double Pianus in Bera

But I thought you can only potential (with magnifying glass) once on each EQ? and 8 times for enchanment ?

Or can one item be "potential" many times? (while it stacks with the previously obtain potential - - highly doubt this) ?

You can use Miracle Cubes from the Cash Shop to reset an item's optional to hidden potential, then use another magnifying glass and get a different potential.