Missing MCA error messages for bad ECC

OS: 14.2-STABLE as of 250403

I seem to have at least one bad ECC DIMM and  was expecting to see MCA
messages in /var/log/messages or to the console (which I have recently
redirected to /var/log/console.log via syslog.conf:

    console.info /var/log/console.log

but I can't find anything in any of my logs. Why am I not seeing them?

Background:

Motherboard: Supermicro X11SCA
CPU: Xeon E-2176G
Chipset: C246
Memory: 4x SK Hynix HMA82GU7CJR8N-VK (16GB ECC)

Bios reports ECC on its startup screen and dmidecode reports

    Total Width: 72 bits
    Data Width: 64 bits

for each of the dimms.

Amanda started reporting checksum errors on large backup files in its
holding disk. I discovered that a large file (200GB) on any of three
disks on this system yields different sha512sum values every time I
run it on the same file. SMART data looks OK on all disks.

memtest86+ finds three bad spots in memory, at 42G, 47G and 53G. I have
4x16GB dimms installed, so I think that corresponds to two bad dimms.

    % sysctl hw.mca
    hw.mca.cmc_throttle: 60
    hw.mca.force_scan: 0
    hw.mca.interval: 300
    hw.mca.maxcount: -1
    hw.mca.count: 0
    hw.mca.erratum383: 0
    hw.mca.intel6h_HSD131: 0
    hw.mca.amd10h_L1TP: 1
    hw.mca.log_corrected: 1
    hw.mca.enabled: 1

Thanks for any insights.
-- 
G. Paul Ziemba
FreeBSD unix:
 8:31AM  up 2 days, 14:38, 11 users, load averages: 0.71, 0.43, 0.39