HI 
there is a problem, a many2many field value get False in onchange of any field in that current form and if many2many is linked to current object

i have many2many field in hr.employee which is also related to hr.employee but it get false in any onchange method in employee form while i have other many2many but they does'nt get False because they linked to different object

have any one you faced the same problem...
plz odoo R&D team please check this issue.

Thanks
Sandeep