TAC its not working for every contenttype

I don't know whats wrong, but TAC is not working like it should. Or not in every case.

I created for my site a category with some terms ... for each role exact one term, so that a member of a role could only change content of his "group" (all members within the same role to set only this term ID). Other members should not get the edit link and not be able to update this node.

This is working for some content types like pages but also own with cck. Now I have one with CCK (using a node reference- feild). For my node 200 of this content type I have the following entries in the node access table:

200 2 term_access 1 0 0
200 1 term_access 1 0 0
200 3 term_access 1 0 0
200 4 term_access 1 0 0
200 5 term_access 1 0 0
200 6 term_access 1 1 1
200 7 term_access 1 0 0

The only one who should be able to edit the node is with the role ID 6. But also the others who have permission to edit this content type can edit it although they have nothing to do with role ID 6 (they don't inherit the right from 6, they don't share the the same role).

Now somebody with role Id 7 can edit and even worse save it successfully. The content is set to the new changed one. The nid in the term_node table goes now with the new ID but also with the old. This means a node has two term IDs. But I don't allow multiple terms.

I have the same Problem with the Versions 5.x-1.1 and 5.x-1.x-dev.

What could be my problem, where should I start debugging? HELP ME! :)