On my phone (Alcatel mt6737m aka Optus X Spirit, android 6.0) I had screen lock set up, and also had "require PIN on startup" (when it asks for pin on every reboot, even before showing unlock screen). And I had google account, which I only set up because it's required for google play. I don't remember username or password for the google account. I still remember the old PIN for the phone.
I did a factory reset via boot menu. Now I got this "verify your account this device was reset" message.
I managed to open settings using one of the exploits I found here, but even if I do factory reset via settings menu, it still asks me to "verify your account". I also tried to set PIN to my old PIN and then disable PIN and do factory reset from settings - no change.
I can start Chrome or almost any other app (if i place shortcut on the lock screen), can modify settings, can start file browser, install apk from sdcard. I can not create a new google account - it shows me the same "verify your account" screen. I can not enble developer options.