The solution, of course, is to name them. Can you share which motherboards you've seen people complaining about?
Remember: DDR4 goes straight to the CPU these days. I'm fairly certain that motherboard makers can make a simple wire connection between the DDR4 pins and the CPU itself without much issue.
https://community.amd.com/thread/217871
The AMD Community knows to avoid Hynix and to buy Samsung. Hynix did improve with some BIOS updates (in particular: increasing V_soc voltage to 1.1 and other tricks). Update your BIOS if you have any issues.
Zen+ dies have better DDR4 compatibility.
AMD's memory controller is actually from Rambus.
The good thing is as more EPYC moves inside DC, there will be lots more memory testing done for AMD.