iOS 8.4 Cannot Search Messages

iPhone 5, 16G, iOS 8.4

iPhone 5S, 32G, iOS 8.4

iPhone 6, 64G, iOS 8.4

After a clean reset and restore backup from iTunes, I can no longer search through my messages, no matter what keywords I typed in, no result in return. I've tried:

1. Reset network

2. Turn off/on iMessage

3. hard re-boot

4. Turn off/on spotlight

5. Switching languages

None of them works! Please help...