To your experience, are these type of crashes HW, SW or it could be anything?
The only reason i had so far for a full freeze was if i OC the first card a little bit to much. Try to lower the OC settings for your GPU0 a little bit.
The problem is that it's happening even when I am not overclocking the rig, i.e.:
POWERLIMIT_WATTS=100
__CORE_OVERCLOCK=0
MEMORY_OVERCLOCK=0
The rig has 12 GTX 1060 6Gb (from different manufacturers)