Apple is claiming that the Towson Apple Store employee contract prevents guaranteed employment at other locations, and the union has filed an unlawful discrimination suit about the matter. On Monday, the International Association of Machinists and Aerospace Workers (IAM) Union officially filed an Unfair Labor Practice (ULP) charge against Apple. The charge , which has been submitted to the National Labor Relations Board (NLRB), alleges that the company unlawfully discriminated against unionized workers at its Towson, Maryland retail location. Towson, Maryland was the first unionized Apple retail location in the United States. It was also one of three locations Apple would be closing permanently in June. While some thought the move could have been retaliatory, it's unlikely that was the case. Apple cited declining conditions and the loss of retailers as the primary reasons for closing. The actual issue lies in a statement that Apple issued as part of the closure.…