disk listed under storage devices but not on the vSAN claim list

Hi,

Setting up an all flash cluster with 2 disk groups per server, each server has 2 smaller all flash disks that will be used for the cache tier per disk group.

The issue is that when I go to setup the vSAN/claim disks, I can only see one of these listed per server, the other disks that will act as the capacity tier all show up fine for each server.

I confirmed that both smaller disks show up under storage devices, any idea why one of these would not be listed to be claimed for vSAN use?

Disk controller is a DELL HBA330 Mini and ESXI is 6.5U2

Thanks