Well, it did for me, anyway.
I successfully updated F25 yesterday (4/19) afternoon, powered down my computer and rebooted in the evening. (I noted the new KDE login animation). But this morning...
Symptoms: Fedora 25 (KDE spin) booted, up to the point of showing the login screen, but the screen only "flashed" for the briefest of periods (about 1/10 of a second?) before disappearing. Rinse and repeat the flashing screen every 2 seconds or so for several minuted before giving up and hitting the reset button.
That didn't help. Neither did a complete powerdown and reboot. I was able to re-install F25 live (got my recent data backed up - whew!), but after the upgrade completed (successfully, I might add), the same thing happened on reboot. The login screen flashes very briefly and disappears every couple of seconds.
I was able to re-install, upgrade and boot F24, which sort-of, kind-of tells me it's not a hardware problem. The biggest difference is that KDE was upgraded to version 5.9 (I think), and F24, when upgraded, is using 5.8. The linux kernel (4.10) and the nouveau graphics drivers were the same on both.
I haven't looked at the KDE forums yet to see if anyone else noticed this problem, but I'm asking if anyone else here has seen this problem (or complaints about it).
I'm glad F26 is only 6 weeks away.