I think it's a bug that I get this verification everytime I login to several accounts from a different IP address.
https://i.imgur.com/4mdCwwtl.jpg
I do not have 2-step authentication enabled on any of my accounts. I am not sure what to do with this verification prompt, except hitting cancel. After that I will be locked out, and must reset Google password.
same problem!
I'm having the exact same issue with FF when I log in via my phone's hotspot or public work wifi. It is MADDENING, and it's Google's issue. I had to take my shared Gmail account off for a journal at my university as I just had to email 8 people to tell them I had to change the password - so pissed and embarrassed!