At this time, the Software Updater is not able to tell if the 32-bit or 64-bit versions (or both) of certain programs, including these two, are installed.
As such, the 32-bit version will be installed, as that version will work on all computers that CCleaner supports, and in many programs, wouldn't have any difference whatsoever in terms of real-world performance.
This is something that our development team is aware of, though, and when a good solution is available, it'll be included in the next available update of the software. In the mean time, you can either install the 32-bit versions, or uncheck them from Software Update and update them manually or through the software's own update functionality.
Thanks CCleaner Team for the update. I understand the challenges, but from a user side it is also weird, when your 64bit installation of an app gets overwritten by a 32bit installation without any notice. Especially if you don't have an a eye on this all the time.
Maybe as some food for thought: You could check the PE-Header of the executable for the IMAGE_FILE_MACHINE_AMD64 in the "Machine Type" section to recognize if the installed binary like "vlc.exe" is a 64bit executable or 32bit executable. Another option would be to ask the user actively if he would prefer the 64bit or 32bit release.
But please see that just as some personal ideas.
BTW: I really like CCleaner and I am using it already for years. Thanks for the good work.