Apple issued a new update for Apple Watches recently — watchOS 9.5. However, some Apple Watch users who took the update had their screens turn green afterwards. The issue usually manifests itself as a green tint on the notifications screen and in the Control Center.
The functionality of the watches doesn’t appear to be affected. However, it is unsightly. Some users were able to resolve the issue by restarting the watch. Both older and newer Apple Watch models have been affected by the issue.
Users on Reddit have been discussing the issue, and Series 8, Series 7, Series 6, and SE users mentioned they were affected by the problem. A photo of a watch affected by the issue was also posted in the Reddit thread. The issue is likely to be corrected with a subsequent update in the near future (hopefully).