This is something I cannot stand. I have two external monitors, and each time it wakes from display sleep they switch around - so the desktops are reversed. It's infuriating. I have tried and tried to find a solution but so far have nothing.
IIRC this happens because some monitor companies are cheap/lazy and assign the same EDID to all monitors of a particular model (EDIDs are supposed to be unique), making it difficult for operating systems to distinguish between them.
This does not appear to be the case, the serial numbers reported in System Information are different.
Are you all using TB3 monitors? My experience with an eGPU using TB3 has been that TB is an awkward technology in any operating system so far, I have to routinely power down in specific order all the way to disconnecting from the wall to ensure the device is detached correctly and will attach correctly next time.
Not for the monitor, but for the dock that's connected to all the monitors (belkin thing)
I had the same, though after three days I just gave up and physically switched the monitors. It shouldn't be necessary, but at least I don't have to deal with it anymore.
The problem is they always switch around between each other so I'm not sure that would solve the problem.
+1 most annoying thing. There is a workaround. Create a new desktop on one of the display, this will then give you options to move app around when you right click on the app icon. Still pretty bad but it beats moving around windows manually.
This is what I'm doing at the moment, but dragging around 2-3 desktops every time I wake my laptop is an extremely draining experience.