Elerium,
Can you confirm that your S3510 SSDs are not contributing to the problem by swapping them for something else? My cluster consists of 4 x Dell PowerEdge R730 servers each with 2 disk groups running VSAN 6.1 hybrid. On three of the nodes, the disk groups consist of an Intel S3700 800GB for write cache and 6 x Seagate Constellation.2 (ST91000640SS) 1TB hard drives for capacity. The remaining node has Intel P3700 800GB PCIe drives instead of using the Intel S3700. I'm currently running 8DV10171 with nvme 1.2.0.27-4vmw.550.0.0.1331820, so I don't believe I'm seeing any of the issues you've described.
