FreeBSD 12.2p1 won't boot on (some) Dell R730xd

[George Michaelson]

I have two Dell R730xd. they have different generation Intel CPU
cards, one has the 8 core, the other the 6 core, duals (so 16 and 12
respectively)

same disk controller (HBA) same memory.

One booted 12.2p1 just fine. The other just won't do it. Bootloops
hard during device probe time.

I played with x2APIC and the behaviour changed, but it hung badly in
USB timeouts.

FreeBSD 13-snapshot boots fine btw. As does FreeBSD 12.1 and priors.

UEFI, BIOS, same-same.

Any clues? Its not important to me, but, if debug is useful to anyone,
PM will find me and I can try things you direct.

-G