To answer your question I will post my summary of the issue-

it has been confirmed with 2 of these motherboards and different memory, CPUs

Thanks for your reply

I am very frustrated. My issue is exactly as the op reports

there are 2 possibly separate issues

1) random post failure at high bclk with fans powering off and bios warning

2) random c1 post reset- where after the post beep but before windows loads, the mono will click to c1 and start the post again. Often this gas no associated message.

The first issue I have only seen at high bclk on confirmed 24h stable settings and seemed initially to be an oversensiyivity to ioh voltage- eg more prevalent past 1.18 v ( 2 mobos tested) the issue although random was reproducible at stock speeds with that voltage tweak. There may be other factors involved though

the second issue seems independent of bclk and is less reproducible but certainly can occur at stock settings. Seems very random an independent of voltages and clocks