After launching CC app today I've got updates for several apps XD included. But after the update I've noticed, that Libraries will not load in Adobe XD, despite being available in CC app itself and other apps like Photoshop and Illustrator.
I've reverted back to Adobe XD version 35.0.12 and everything works fine. I'm on Windows 10, but since it's ok in the older version - it should not be a problem on my end. For now, I'll stick with this one and auto-update turned off. Hope it will be fixed soon.