When closing the scheme editor, the KCM reads stdout of the editor to figure out what's the saved theme so it can be selected in the list.
This printout confuses it and has it select a non-existing theme breaking the current selection.

Edited a scheme, closed editor without saving, didn't have the list reload.
Edited a scheme, saved it, closed it, list reloaded and index was still correct.

I don't think that this particular printout was used by a shell script or something?