HBM2 had a difficult period of 12 months. The standard of memory has not followed the path of its predecessors. If that was the case, we should have seen widespread deployments of AMD and Nvidia on mid-range and high-end products. Instead, the AMD Vega 56 and 64 are currently the only mainstream GPUs to support the memory standard.
One of the rumors of HBM2 last year was that the clock speeds were well below the AMD GPUs reach the expected bit rates of 2 Gbps per pin (Hynix adds speeds of 2.0 Gbps to its HBM2 offerings in August 2016, then deletes them in 2017). Samsung, however, may have found a solution to this problem, and plans to introduce a new HBM2 clocked at 2.4 Gbps per pin.