Without reviewing the contracts and MOUs, it's difficult to be precise. However, generally, if you have a current local contract in force, and the union advises you to violate the terms and conditions of that contract, then that would be a breach against the adversely-affected employer. You simply cannot violate the existing local contract.
Re penalties/fines, if those fines are imposed against you for refusing to violate the existing local contract, then that, too, would be a breach of contract, only this time by the union against the workers.
Thus, there are two different potential breaches: by the local workers/union against the employer for failing to act in supervisory roles that were agreed to under the contract; and by the main union against the local workers/union for imposing fines/penalties for refusing to violate the local contract.
Hope this helps.
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