The issues depend a lot on the displays (some displays don't expose a serial number, or have the same serial for each display), or how it's connected - Thunderbolt dock? USB dock? HDMI? (what adapter?) DisplayPort? (again, what adapter?)
That’s a good point, it may help me if begin to experience similar problems.
(Which may be tomorrow, because I mentioned that I don’t remember having those problems.)
I’m currently using a thunderbolt adaptor with HDMI and DP, so I guess that makes it pretty easy for the OS to consistently identify the displays.