I tried to do a search for this subject but I couldn't seem to find one that fit my scenario exactly.
I was deleting some old recordings today and noticed that even though they disappear from the UI and seem to be gone, if I go to the actual folder, some of them are still there. It seems like some of them do get deleted, but not all of them.
I am running the DVR on Windows 10 and am staying updated as you release the Beta DVR (just updated this morning in fact).