All ID fields of all entities within the zabbix database are prefixed with two nodeid's (owner and creator), ofcourse when a node has been converted to DM node.
A converted 'stand alone' or child node works fine by itself.
A master node receives all (where applicable) data from a child and has data from multiple nodes within its database.

It seems that a 1.6 master node sometimes prefixes these ID fields in the wrong way.
Below are 2 table contents, one of my child node, one of my master node.
Child is NodeID 1
Master is NodeID 10
Own id's are correct (00)1001 for the child and (0)10010 for the master

But it seems that the child's data in the master database, in some cases, is wrong. Look at the (just 1?? it wont sync the rest) nodeid 1 entry in the master's ids table. It's prefixed with 101.

I don't know in which component this is caused, i expect zabbix_server and not the gui.
I suspect that the cause of this, is also the cause of most other DM related issues on the forum and the bug tracker.

ids table from my 1.6 child node (upgraded from 1.4)
=============8<============================
-------------------------------------------------------+

-------------------------------------------------------+

-------------------------------------------------------+
=============8<============================

ids table from my new (added later) 1.6 master node
=============8<============================
mysql> select * from ids;
-----------------------------------------------------+

-----------------------------------------------------+

-----------------------------------------------------+
=============8<============================