When I quit the advanced KDM options (Watermarking) with 'Okay', the KDM creation window disappears - it goes behind the DCP-o-matic main window. That’s probably a bit surprising for beginners. Okay, beginners should not make KDMs or choose advanced options anyway ;-) This may only happen in OS X.

I created 6 different Sony SMPTE Test DCPs within the same film/project, carefully switching apps, renaming CPLs and changing encrypted checkbox.

I then went to creating the KDMs with the same project open in 2.15.17. I was able to select the three encrypted CPLs from the list/UUIDs, and their different CPLs were correctly displayed beneath - however, the %f flag in the KDM naming dialog is chosen from the current set CPL under DCP tab - not from the CPL that I selected above for the KDM creation.

In this case, the CPL name under DCP was still set for the last CPL I created - DOM21517 - but the CPL I selected for the first KDM to be generated was DOM21410.  The KDM file was hence named KDMDOM21517encLinden-Theater_FrechenSaal1.xml - but was created for the DOM21410 CPL. As this is only file naming, I changed it manually to KDMDOM21410encLinden-Theater_FrechenSaal1. Another consequence was that, since the selected %f under these conditions (multiple encrypted CPLs within one project) stays the same, the KDM writing will always use the same file name, thus overwriting previously generated KDMs.

So, long story short, I guess %f should not be taken from the currently set CPL name under the DCP tab, but from the chosen CPL in the KDM creation dialog. No big deal if you know what happens, but should probably be corrected - there certainly are good reasons that KDM file name and CPL name and annotation text in the KDM comply - even if users are probably not advised to have multiple different encrypted CPLs in their project.