Fulltext:word failling on upgrade to 4.4.4

Dear all.

i’ve upgrade my RT server from 4.4.0 to 4.4.4. All are running well, although i’ve can’t use the simple search with “fulltext:word” as before. I’m using Postgresql as DB.
I try to remove the AttachmentsIndex table in database, and run a new “rt-setup-fulltext-index” command. It complains about some string too long for the tsvector. But at end, i’ve got a index for searching.
The search is correct when i’m using a “New Search”, i can define the "Content matches " creteria, and get back all the concerned tickets.
So why the simple search “fulltext:word” not running ?

To be complete, i’ve installed a new fresh RT system to try this. After i’v created some tickets and interact with the new RT system, the fulltext:word search correctly found the concerned tickets.
My problem seems to be due of an upgrade.
If someone could help me in this issue please?

Best regards.