Google Photos on the web forgets how to sync with mobile app
Source: Android Authority

TL;DR
- Users have noticed a recent ongoing issue with Google Photos.
- Anything saved on the web is not syncing back to the mobile app.
- The problem appears to have started last Thursday.
Issue Overview
When you save a photo in the Google Photos app, it is backed up to the cloud, allowing you to view the picture on the Google Photos website. Conversely, adding an image from the website should make it appear in the mobile app. A bug is now preventing this two‑way sync.
User Reports
A large number of Google Photos users are reporting that:
- Photos continue to back up from the mobile app to the cloud.
- Uploads made on the web do not sync back to the mobile app, leaving images missing on mobile devices.
While the issue appears widespread, some users (including the author) have not experienced the problem; syncing from the web to the app worked on their devices.
Timeline
- Last Thursday – The bug was first reported.
- Current status – Google has not issued an official comment. A diamond‑level Google product expert confirmed that the Photos team has been alerted, but no timeline for a fix has been provided.