A checksum from graphic and keyboard devices is build on startup. Kdmconfig compares the last saved checksum with the one created on startup. A Difference is interpreted as a hardware change and the execution of kdmconfig is triggered.
With some Graphic Cards and Keyboard combination this checksum differs between startups.
If you are certain that you hardware hasn't changed run kdmconfig
configure and test your settings. Edit file /etc/openwin/server/etc/OWconfig and set variable TestedByUser from 1 to 2.
With the above settings kdmconfig will ignore any Hardware changes. However if your Hardware has changed you will have to run kdmconfig manually.