By January 2018, it was reported that 76% of Phase II construction was completed. However, a few months later it was discovered that multiple sections of cement walls of the new Metro stations were improperly designed, making them prone to water infiltration. Construction contractors took action to fix the problem and said it would not impact the extension's projected 2020 opening. The contractor Capital Rail Construction (CRC) and the supplier Universal Concrete pledged to fix the problem, and CRC also committed to spraying the concrete with a special sealant every 10 years as needed. Later, in May 2018, the federal district court in Alexandria, Virginia unsealed allegations by a former employee at Universal Concrete Corporation that precast concrete used in five of the six Phase 2 Silver Line stations had been produced from aggregate from a different quarry than the one specified in construction contracts. Officials took four core samples from each of the five affected stations for microscopic testing to determine whether the panels complied with project requirements. That July, the governments of Virginia and the United States sued Universal Concrete for providing false records and defective materials. In September 2018, it was revealed that about 400 of the concrete rail ties on Phase II were defective, in that they caused the rails to bend outward. However, Metro and CRC were not able to agree on a solution before that December.