When using regular expressions in the Windows FileFinder, the returned constant portion contains a trailing file separator. The paths returned from the recursive searching function does not. When attempting to compare the pattern, this difference results in a failed match. This will result in a valid file path not being searched for the desired files, and possibly not collecting the object.
I think this was fixed ~r1221, in 2012. Trailing separators are stripped off of const portions now. So I'm closing this bug.