Google "Find my phone" asks for authenticator code

Yesterday I forgot my phone at home. I realised this in the office and I thought to myself that I either left it at home or left it in the car or even lost or misplaced it. Put this was I was not 100% sure where it was. So I looked around my office desk and the kitchen where I made coffee. I then went down to the parking garage to check my car. Since I did not actually recall seeing or using it at work that morning I assumed that I probably just left it at home.

However since this is not the first time this has happened I usually like to put my mind at ease by searching google with "find my phone". I don't use the feature often though it does come in handy in instances like this. However this time Google came up with a map however required me to sign in to confirm my identity. I am sure it has asked this before however this time round it just keeps on telling to to sign in and when I click the sign in button the same screen pops up with the same error.

I managed to circuimevent that by going directly to the find you phone web page first and it allows me to choose which phone then comes up with a full screen sign in page. Since I know my user and password I am able to do so however then it asks for my authenticator code. Obviously, because I do not have my phone on me I am unable to provide it with the code. On the same laptop I am accessing my Gmail no problem as I have previously logged in and it was told to remember me. I tried alternate methods of login it but it offered to send a code to my phone which I did not have on me. The other was the recovery codes which I have a backup copy of at a different location.

I had to wait until I got home to confirm that my phone was indeed there. Why does Google ask for my authenticator code to confirm my phones location? I tested out the functionality at home and while it also asked me to sign in it did not ask for my authenticator code. Is this just a bug?