Bulk Update not working for me

i there, I just migrated a D6 Site containing tons of nodes to D7. I now wanted to use this module und bulk-updated the two relevant content types.
what's strange:
- type a working fine

- type b (having much more nodes) does not throw any error or so on update but SSP does not show
editing a node of type b shows a checked checkbox (for each node!) but checking field_data_field_socialshareprivacy shows they are NOT in there. re-saving a node of type b does result in a new row in field_data_field_socialshareprivacy and does show SSP.

is there anything wrong with bulk update? is it possibly collecting information on nodes to be updated first and runs into a timeout- as otherwise at least SOME nodes should get updated?
any help appreciated TOM