But your problem is very much out of scope for what a real ESXi/Vsphere environment would actually be used for or how it would be used. I hope you understand where I'm coming from. That is a more realistic deployment scenario and one more likely. I would recommend using the remote console and your client's USB ports/Drives. IF you want to on the fly attach USB drives to a VM. You're trying to do something that simply wouldn't be needed in an actual enterprise setup. Clearly the drives work and the hardware works just not in the specific use case you have that is by all appearances decidedly out of character for the environment.
This has more to do with the design concept and how the VMware was made and not so much with a driver issue. In this case you would either give the user the abiltiy to use VM's console and attack their own USB drives via that console interface, OR direct path I/O disks to the systems on a more permanent basis. From a VM perspective it seems counter intuitive for the design. So if you mount the card and use the drives it works fine then you can directpath I/O the drives to the VM's in question but you really want to be able to hard map the USB ports to the VM so you can plug in a USB drive and access on the fly and swtich drives.
HPE Insight Diagnostic 3 hours run reports no faulty hardware. On both servers I use ESXi 6.0U3 free version but on the M元0 I tried also 6.5 U1 version.
Note that I have a second Proliant M元10 gen8 and I can pass successfully both AMD FirePro 4900 and a second Renesas usb 3.0 pcie card to a Windows 10 64bit VM (I used pciHole.start = "1200" pciHole.end = "2200") Thinking the usb card is broken I tried it with the same server but installing Linux Ubuntu 18.04 LTS 64bit on bare metal and all is OK. If I does not passthrough the usb card and instead pass only connected HDD device to VMs all is OK. With the VL805 I got only one time PSOD and unrecoverable NMI log, but every time I shutdown the Windows 10 VM, this cannot restart until the next ESXi reboot. With the Renesas all seems ok, but if I connect a usb 3.0 external HDD, every time I turn on the disk I got always a PSOD and in ilo log (hpe ipmi) I found a unrecoverable NMI and a pcie error. I have installed the card and passthrough it to Windows 10 and Scientific Linux 7.5 both 64bit versions. I tried both a Via VL805 based and a Renesas μPD72020 based. I have a HPE Proliant Ml30 gen9 (firmware updated to latest version), and I tried to add a pcie usb card.