I have been having this problem for a very long time, and so far have not found an answer - even going through Chat in Adobe Support. (They didn't seem to know the answer, and when they couldn't provide one, they actually hung up on me.) I hope someone out there has an answer.
When I check my Activated Devices in my Adobe profile online, it shows two, both of which are activated on or around the same day:
<my computer name> on WINDOWS_64
<my computer name> on WINDOWS
It says just above that:
"You can install Adobe applications on more than one computer, activate them (sign in) on two, but use them on only one computer at a time. To activate apps on a third machine, you’ll need to deactivate (sign out) on one of the two current computers first."
So, according to my profile, per Adobe, I should be able to use my Adobe license on two devices at the same time. However, my one computer is acting as though I have signed in twice and therefore using both license simultaneously. If I deactivate one of these, both get deactivated, and if I run Creative Cloud and re-log-in, both devices again show as Activated. If I uninstall and reinstall Creative Cloud and all Adobe apps, the same problem comes up. I even had a computer crash a while back and had to install everything from scratch, and even with that, the same problem came up. No matter what I do, I cannot make my profile see only one computer as Activated - and that is in fact the truth, I am only using Adobe on one computer, not two - and so I have no way to use Adobe on a second computer without Deactiving the only computer I am currently using - which means the idea of running Adobe on two computers is misleading because it simply doesn't work.
How do I get Adobe licensing to see that I actually am running Adobe on only one computer, not two, so that I can, if I desire, install and use my subscription on a second computer without having to deactivate my one computer first? Especially since I should be able to use it on two computers, according to the wording my license page gives me?
I encountered this very same issue. Have you actually tried to activate on a second computer? If not, give it a try and see if you get an error or not. When I was looking into this, I actually had FOUR entries on my list of activated devices - two for each of two computers, one with _64 and one without. I deactivated both entries for one computer, so then I only had two entries, both for the one (new) computer. Then, by chance, I was logged out of CC while looking at these entries online. The list of activated devices refreshed and only showed one entry, the with _64 at the end. When I logged back into CC, the second entry reappeared, the one without _64. Given that I was able to use the apps on both machines when there were 4 entries, and the fact that one of the two seems linked to the machine and one to CC app, I think Adobe does see the two on one system as a single activation. Give it a try!