Also, maybe try resetting the Photoshop preferences. Sometimes the PS preferences files get corrupted and cause strange issue. A few days ago someone else had face detection issues that were fixed by resetting the PS prefs. You can see that post in the forum which is the latest post right before yours. So it would be worth trying this.
Go to the Preferences and to the General section. Select Reset preferences on quit. Then restart Photoshop. Let me know if this fixes it.
Damon Bell
