A few weeks ago I talked about Identifying your controllers and installing the correct firmware and drivers for a vSAN environment.
Even though you follow my recommendations vSAN Health Check still showing a warning for the vSAN cache tier controllers.
Don’t be afraid, there’s a bug that prevents Health Check to correctly identify PCIE/NVMe controllers and so the alarm is triggered, even with the certified driver and firmware installed.
It took me some time to find this information, so I thought I could save some of your time too.
Here's the KB2146676 that outline this bug.