I have some new information. The only cluster where this "Alien robot with a magnifying glass appears and the donut just spins and spins forever" is a problem are all hosts that where upgraded from / U1d to U2 GA using the patch-baseline. For some reason, the problem with "Failed to load crypto64.efi / Fatal error: 15 (Not Found)" did not occur there.
All the other vSAN clusters in this vCenter were updated via the ISO baseline and all those hosts DO NOT have the problem. The pNIC diagnostics pane/tab works fine on all of those hosts.
Conclusion: in my environment, all hosts upgraded to U2 via the ISO have working vSAN pNIC statistics. Only the hosts that where upgraded to U2 via a patch baseline are affected.