Hi,
I think I have found the solution.
After several tests, probe with several ODBC drivers, it turns out that with Verison 8.8 libmyodbc8 (yum install mysql-connector-odbc) the realtime of the ps_contact table does not work correctly (
at least for me). I change to a verison earlier than 8.0 (5.3) and the problem was fixed. I have discarded the verison the odbc from this page.