Ccleaner finishes too quickly

I upgraded to v5.33.6162 a few days ago, and only today did a total clean of my system. I run Win10/1607 and have Ccleaner set for a simple 1x overwrite. A cleaning usually takes a few minutes, but sometimes when I've put big video files in the trash, it can take as much as 15 minutes. This is fine, I'm not in a hurry. But today I had close to 9GB of files in the trash and Ccleaner whipped through the whole process in under a minute. The files are all gone, but I really don't think there was time to overwrite them even once. Any ideas, anyone?