After user registration (with some welcome waves) search inbox is empty

In our servers when we create some user, we create also some waves for him/her (a welcome wave, and other sample waves). But with the new changes in search code, the inbox search returned after user registration is always empty:

10-feb-2012 12:01:06 org.waveprotocol.box.server.waveserver.MemorySearchProvider search
INFO: Search response to 'in:inbox': 0 results, user: XXX

after a server restart:

10-feb-2012 12:13:35 org.waveprotocol.box.server.waveserver.MemorySearchProvider search
INFO: Search response to 'in:inbox': 7 results, user: XXX

Seems that there is a unsync between memory index and the file store.