Large resfiles folder in C drive, game installed on different drive

Every single time I play eve, enough files gets added to C:\CCP\EVE Online\ResFiles to fill up that partition entirely. My cache and resfiles folder are supposed to be in my game folder on a different partition entirely. If I delete the files in the folder in C it gets redownloaded next time I need to load something, despite the fact that I have installed the full client. Is this intended behaviour or is this a client bug?