When I have used issue scanning, and cleaned up the listed stuff, and I hit the 'scan for issues' button again, it sometimes finds one or two files that weren't cleaned up (or maybe weren't one the first scan) :\

why is this? do windows create useless files so fast, or is it that the scanner leaves something out on the first scan?

Here's some basic information:

#1 - `Issues` is not about files [unlike the rest of CCleaner], it's about registry entries.
#2 - When you remove orphaned registry entries, those entries orphan some more entries that were depending on them. It is very normal, and a good thing. Simply continue running `issues` scans until it is out of finds.