My console(PS4) has that white stuff on back in vents and I have yet to take to the cover off. I thought it was from running my humidifier with vicks vapor rub(which I run 8-10 hours at night time 7 days aweek) but now that I see that somebody else has it so Im not sure about that.
You may have to zoom in since I took a quick pic but up close it looks like dry liquid and thats why I assumed it was the humidifer.
And me wiping it off which in fact comes over very easy and seems powder like. Has no smell also to it lol.
Edit: The white stuff was also not there on the day that I received it from Amazon on launch day. Noticed it about a week ago but as I said above thought it was the Vicks Rub in the humdifier and just moved it to another room. I'v wiped it down now and will see what happens in another month or so.