We have several users that linked their PlayFab Accounts with their Google Accounts, both on iOS and Android. On both, we're using the old Token Auth functionality (also we have to stick to it, since account switching is a problem with the new server auth method (https://community.playfab.com/questions/12038/authenticate-via-google-serverauthcode-issues.html?childToView=12437#answer-12437).
The current issue though seems to be only UI-wise in the GameManager - it simply doesn't show the linked Google accounts. It shows GameCenter and Facebook fine. Also there's no issue with logging in. We just tried to create a segment to see how many of our users linked which account type and Google simply shows zero. Also on the single player's profile, there's nothing visible.
We don't know if it's the same issue if using the server auth code method.