Hi.
Just did some test with W Elements.
If I create a sample set the loop markers and save the file, Kontakt can see the loop points.
If I create a sample, set the loop markers and export the file, Kontakt doesn’t see the loop points.
However opening the exported file in Wavelab again, the loop markers are there.
I don’t know what’s technical difference between exporting and just saving an existing or modified file, but in one case Kontakt can see the loop markers, in the other it doesn’t.
Try saving the file instead of exporting.