I have recently updated from LR 5 to LR 6.7 (Win 7/64). From this point it happens almost every time that after importing RAW files and automatically converting them to DNG some of the original RAW files are not deleted. I have set my cameras to take RAW and JPG. When I import the photos (LR option: treat them as one image) normally the RAW is converted to DNG and the JPG is kept as well. The RAW is deleted. Now I have found out that some of the RAW files remain in the folder where I also find DNG and JPG. After some reproduceable tests it seems that my Panasonic RAWs don't show this effect, it happens only for some Olympus RAWs. It's not always the same file which "does not work". It changes from import to import.
Can anyone reproduce this or is this maybe a known issue?