The context menu for a filmstrip thumbnail in Develop sometimes shows Metadata > Save Metadata To File rather than Save Metadata To Files when multiple photos are selected.
To reproduce:
1. In Develop, select multiple photos in the filmstrip.
2. Right-click one of the selected photos and roll the mouse over Metadata. Observe that Save Metadata To Files is shown.
3. While the context menu is still showing, move the mouse over another selected photo.
4. Right-click that photo and roll the mouse over Metadata. Observe that Save Metadata To File is shown, not Files.
5. Hit escape to close the context menu.
6. Right-click the same photo as in step 4, and observe that Save Metadata To Files is now shown.
See this screen recording: https://dl.dropboxusercontent.com/u/21811200/filmstrip-save-metadata-bug.2017.03.03.mov
See this thread for the original report: https://forums.adobe.com/thread/2285258
CC 2015.8, OS X 10.12.3