Sorry to say that I just discovered this topic because this problem (which I had never experienced before) started for me AFTER I upgraded my iMac 2012 to High Sierra 10.13.5 recently. I'll describe it briefly, since it could be a new iteration of an old problem, or a new one: I can wake the Mac up from "sleep," with the keyboard (which is wireless), the desktop appears and, while nothing's missing, everything is "grayed out," and it takes about 45 seconds to a minute before the color returns. (Because it's Pride Month, I think of this as my computer waking up in Kansas and then taking a while to get to Oz.) At which point, my bluetooth mouse is not recognized. I can fix that by turning the mouse off, and then turning it back on, but this won't work unless I wait about a minute to 90 seconds after the color returns.
Bottom line? A wake-up function that used to take perhaps 2 to 3 seconds now takes about 2.5 minutes. So, it looks like Apple didn't solve this problem. Maybe they decided to spread it around more broadly so they can claim it's a feature rather than a bug?
I actually was considering buying a new iMac, but I've put that on hold. If this kind of thing is going to be a regular occurrence, I may go back to Windows. It's so buggy and crashes so much that users having to dive into the code to fix things is both expected and accommodated. With a Mac, you're just kind of stuck with whatever Apple gives you, which is generally nice, but does sometimes look astonishingly like the flip of a middle finger.