KL lost my bags twice and both times they got stuck at AMS and both time the KL handling agent blamed DELTA.
According to the first agent, it is the way DELTA loads bags that makes it difficult for KL to unload and transfer at AMS and the other said DELTA tags do not scan properly in AMS, neither reason made any sense to me at the time and still don't make sense today.
It would be nice if DELTA allowed KL access to their baggage tracking tech.