Messages: Advanced search doesn't work finding by label on other languages

1. Go to Messages 2. Click Compose Message 3. Send two messages to two differente students (one with Label:Normal and other with Label:High) 4. Go to Sent folder 5. Click Advanced Search 6. Unchecked "Subject" and checked "Label" 7. Search for text: high. OK. Message is found 8. Search for text: High. Wrong. Message isn't found 9. Change language to Spanish 10. Go to Mensajes Privados 11. Search for text: alta. Wrong. Message isn't found 12. Search for text: Alta. Wrong. Message isn't found 13. Search for text: high. OK. Message is found On Spanish search for alta should work.