com.apple.mail Mail Downloads folder Yosemite

[dnbreaks]

I just noticed that my user/library/containers/com.apple.mail/data/library/mail downloads folder has 904 folders in it. Apple Mail settings are set to remove unedited downloads when Mail quits, but that does not seem to be happening. I'm not sure if it has been acting this way since updating to Yosemite quite some time ago, but the regular library/mail downloads folder is empty. And when I open a new attachment a folder with that file is created in the containers directory, but not the regular one. Is this normal for Yosemite or is there a way to not have a new file & folder created every time I open an attachment?