Re: Foundation failed on Nutanix nodes with error log shown in details.
Very sorry for the delay on this, but I'll give a try...
Yes, this does not look like an ISO issue. The error indicates this is a timeout during or after the loading of packages and the reboot of the CVM after phoenix completes its imaging. - Did the Phoenix ISO get Plugged-out from the IPMI's CDROM/ISO virtual device? - Did the node boot into the hypervisor? - if so, there should be a first_boot.log to inspect (exact location depends on the specific hypervisor). - Might there have been any network slowness accessing the IPMI?
There have been reports of non-reproduceable timeout errors of this sort, some of which suggest either network timeouts, or delays from certain Hypervisor versions. But that should not be consistent.
If this is consistently occurring for the NX-6220, I would recommend trying a different version of Foundation, as 3.7.2, 3.8, and 3.9 are now available.
Otherwise, if this is still occurring, it might be worth opening a case to investigate, as some Foundation/Phoenix issues can be rather involved.