this is happening in production on an iOS app and we do have multiple users complaining every day.
As a test case we did the following:
1 - go to Google Photos app and did check the option to show photos & videos in Google Drive;
2 - try to clear safari history;
3 - login again.
The result is the following:
1 - we do have success requesting several pages with photo-metadata through Google Drive api v3;
2 - Through the id that we get for each photo we do try to request an image for a specific size through
https://drive.google.com/thumbnail?authuser=0&sz="size"&id="photoId"
Step 2 fails with a http 404 and did not change nothing on our side. It is happening in all devices that we tested, which means that something changed or is not working properly with drive.
Meanwhile we've been told by someone (not Google) that Google Drive is no longer the best way to access Google Photos. Because this data source is in our product, it is important to know what is the correct / best api to access Google Photos now.